After a very quick search, I found CNN saying this:

In just the first four months of 2024, prosecutors launched criminal proceedings against almost 19,000 soldiers who either abandoned their posts or deserted, according to the Ukrainian parliament.

After slightly more searching, we find El Pais saying:

... 81,167 cases registered by public prosecution since 2022. Military personnel consulted by media such as Hromadske or LB claim the figure is at least 100,000; the equivalent of 10% of all personnel currently serving in the Armed Forces of Ukraine.

So 100,000 doesn't seem unreasonable at all. This was a very easy internet search. There's lots of similar information out there. I recommend doing the search yourself and posting the results next time. You're welcome.