I am reporting this because I think mailspring is a good idea and I hope it succeeds. However it currently does not work at all for me. I have the latest Kubuntu installation (22.10). I installed MailSpring via the Snap Store.
After the installation I signed into one of my gmail accounts. This succeeded but shortly thereafter the entire computer OS started freezing up, not just the mailspring app. I restarted the computer several times and tried again with the same result. Mailspring is virtually unusable for me currently. It’s a pity - it looks nicer than Thunderbird.
My OS runs fine otherwise. I don’t have any other applications crashing and the OS crashing has not happened before. Good luck.