Are you sure tsmemcache is production ready? I ran a short test today and the whole thing just tore apart a the seams!
Several problems straight away:
1) Many errors appeared in the Message history along the lines of: [Mon, 19 Apr 2021 16:21:32 GMT] [Error]  AprMemCache::Put error: Internal error (specific information not available) (20014) on key rname/cb_Iv6yX0gwkPM5jgKHHMon/XblePH60s6SPSCP_RIW1n@@_, value-size 72
2) Pagespeed refused to optimise anything - because of the recurring errors.
3) The stats page broke. Infact the whole memcache stats functionality doesn't appear to be implemented at all. The command just errors out.
What was the "tiny patch" you talk about because the first impressions I have is the whole plugin incomplete, broken and largely unmaintained. Such a shame.