https://ohioline.osu.edu/factsheet/HYG-1422  Hi there, I thought, even though you appear to be on top of things, that I would start by attaching a Blueberry fact sheet from OSU. A lot of good information in the fact sheet. While I didn't find anything specific about the 2021 late storm, I think you could be on target. I have several bush plants that lost all of the buds due to freezing temp below 28 degrees for about 6 hours. The leaves are very slow to come out and seem smaller than usual. Having said that, I also lost a couple bush plants to Vole activity. I have never had that before but really got hammered this last winter. Make sure you check the bottom 6" from the soil up for gnawing of the bark on the bushes. Also look for small holes about the size of a quarter. If you find those, dig around and see if they ate the roots just below ground. My plants were completely girdled. If your bushes seem healthy otherwise, it may just be the weather. If you do suspect a disease, I am going to attach a link to OSU PPDC, plant, pest and disease clinic, in Columbus. https://ppdc.osu.edu/submit-sample    This is a good way to get a positive ID if you suspect a disease, so you can approach the problem with better success. There are instructions on this site. This service does have fees. I hope you have great success with this.