The cicadas should not bother the Junipers, fortunately. As for twig/branch dieback, causes can be challenging to differentiate. Usually, with Phomopsis (the more prominent among Juniper pathogens in cooler weather), twig blight is more widespread and affects a larger proportion of branch tips. Here, the damage seems highly localized, so mechanical damage or root loss is more likely.

You mention that watering is at a minimum but that the highest-elevation individual stays more damp. Might something be wetting the area inadvertently, like a pipe leak, downspout outlet, or irrigation running for other plantings in that part of the yard? A berm does tend to improve drainage in general, though subterranean obstacles and changes in soil compaction might still impact drainage from one plant to the next, even in the same row.

Are the plants monitored for water needs during hot, dry stretches of summer/autumn? While Juniper are very drought-tolerant, they do benefit from supplemental watering when harsh conditions are prolonged. A couple of recent autumns have been quite dry for a decent length of time, potentially stressing roots for plants preparing for dormancy. Perhaps the berm actually drains too well for situations like this, where periodic watering may be helpful depending on weather. (You can always monitor to determine if watering is needed by feeling the soil about five or six inches beneath the mulch layer; if cool and damp, it should be fine; if warmer and drier, it may need soaking.) Winterburn symptoms look similar to those in the photos, and is promoted by insufficient moisture or that which is tied-up and inaccessible by being frozen. More exposed soil like that above-grade in a berm might be prone to this phenomenon. With evergreens, winterburn symptoms don't always show-up right away, often not manifesting until sometime in spring.

Whether due to too-wet or too-dry conditions, root loss can result in dieback of foliage or branch tips since the remaining root system can't support all of the top growth. The only solution for this is time to allow the plant to regrow new roots, while correcting for the condition that promoted dieback - avoiding overwatering or irrigating when needed. This is not to say it's the only possibility, but moisture-related root issues are one of the most common causes of plant ailments when a particular pest or disease is not evident. As you mention, we do not see signs if insect pests, nor any clear-cut symptoms of infection (since those most common to Juniper cause more widespread, tip-concentrated browning).

For now, trim out the browned/drying stems and monitor for additional changes in the plant's appearance or performance. Fungicides are only preventative measures, and aren't effective once symptoms of a pathogen manifest. They may, however, protect new growth emerging after a treatment from infection, though Junipers don't always produce lots of new growth later into the summer beyond their spring flush. Here is more Juniper twig blight information: https://extension.umd.edu/resource/juniper-twig-blights

Miri

Foliage color changes can depend on stage of growth, nutrition levels, or changes in root health (since they supply the foliage with moisture and nutrients). Young needles on many evergreens tend to start-out either paler or with more of a bluish coating (for those with normally blue-gray-green leaves), which is a protective wax layer that helps to keep them shielded from strong sunlight and desiccation while they mature. (This is more important in their native habitat than in our gardens, which aren't nearly as harsh.) Some greener Juniper varieties have new growth which is a bit yellowish before it greens-up fully. Darkening of overall color might also be due to maturation processes, especially since lightening and browning indicate desiccation and dieback. If an otherwise healthy blue-green Juniper were to experience damaging levels of drought, for instance, it would take on a duller, paler version of its normal hue before more brown tones take over. In these photos, the paling and somewhat straw-toned color change suggests the damage is not due to a twig blight, since those usually turn the foliage a warmer, deeper tone of brown (as per the images in the afore-linked webpage).

Similarly, twig blights (and other foliage pathogens in other species) usually afflict multiple growth points at the same time, and occur on most or all plants when in the same area, since weather conditions for infection are shared and the group has similar susceptibility due to any shared sources of stress. (Environmental plant stress can make them more vulnerable to infection or pest outbreaks.) If the color change here were due to twig blight, it's likely the other Junipers would be symptomatic, as well as any one of the plants having symptoms manifesting on a larger number of branch tips.

Soil drainage/wetness issues could still be a possibility. We can see the neighbor's nearest downspout, and it looks like it goes underground, but we can't tell to where. If simply buried in that general area, perhaps the outflow is seeping, underground, into the root zone of the afflicted Juniper during periods of high rainfall. Unfortunately there isn't an easy way to examine root health outside of digging-up the plant in question, which of course would be a measure of last resort due to the stress it would cause the plant. It's good that the soil doesn't seem to stay wet in that area for too long, though perhaps the surface conditions are misleading if wetness in the deeper layers is present but undetectable.

Improving drainage post-planting is difficult, because any dug-in amendment can damage roots in the process. For clay-based soils (most of central MD), using sand as an amendment can actually result in worse drainage, so is not recommended. Instead, adding organic matter such as compost helps promote a crumblier soil texture over time, resisting compaction and allowing for better oxygenation of the soil by keeping the soil pore spaces more open. For new plantings, it's added as a mix-in with the native soil; for existing plantings, it's added as a topdressing of about an inch, under any mulch layer used. Over time, soil life works it into the soil around the roots.

Weather plays a large role in disease severity and spread; usually, drier weather results in reduced outbreaks. Once these symptomatic stems are trimmed off, see if new ones appear as we move through the summer.

Miri