I suspect from your photos that you may have an infestation of Annual Bluegrass (Poa annua) in your lawn.  Poa annua is a winter annual that germinates in the fall after soil temperatures drop below 70 F, overwinters and prolifically produces seed in late spring.  Pre-emergence herbicides can be used in the late summer.  Post-emergent herbicides are available too, but may require professional application.
Here are links to articles on annual bluegrass and it's control: https://www.canr.msu.edu/resources/annual-bluegrass
https://turf.purdue.edu/annual-bluegrass/
https://www.extension.purdue.edu/extmedia/AY/AY-41-W.pdf
https://cals.cornell.edu/weed-science/weed-profiles/annual-bluegrass
https://turf.purdue.edu/which-is-it-annual-bluegrass-or-kentucky-bluegrass/
https://turf.purdue.edu/poa-annua-poa-trivialis-in-lawns-and-athletic-fields/