Canon R8 Soft Photos but Sharp Video

[aarphotos]

I have over 15 years experience in sports photography. I currently shoot with the R3 and R5 professionally. I picked up the R8 recently to have a body to shoot friends and family's kids sports games for fun. I shoot with the RF to EF adapter to my 300mm 2.8 and 400mm 2.8 lenses. I've tried multiple combinations of AF, shutter, file settings etc. All my photos seem like they've either focused just in front of my subject or sometimes nailing focus but really soft. I switch to video and they turn out tack sharp. I've tried still photos and it just doesn't doesn't look sharp. I use the same adapter and lenses with my R3 and R5 without this issue. Is this just the R8 not having a full mechanical shutter? Should I try to the R7? 

[MomentOfZen]

Are the issues not related? With all due respect, by scattering related issues among a thousand separate posts, the consumer has a harder time diagnosing their particular issue because the search terms, while similar, may not be precisely the same. By participating in threads regarding other similar issues, we’re leveraging the power of shared communication. My issue was relevant to OP’s. If we put our heads together, perhaps we can reach resolution. But by scattering similar issues, resolution becomes nearly impossible, as no one can search every single post. Why even allow commenting at all if not for the power of combining our individual knowledge into a single point of problem solving? I urge you to please reconsider this policy. Thank you.