Mac Mail Corrupting Attachments Since Tahoe Update

Since updating to Tahoe, the native mac mail app has started corrupting email attachments. This has only started happening since the update and is continuing to do so even after the latest incremental OS updates.

I've never had this issue before in many years of using it, just wondering if anyone else is seeing this? I use yahoo through the auto setup process with auto sync on. Multiple people are reporting that my attachments are corrupted, with glitches across them, be it jpegs, PDFs etc. Sending through a web browser works fine and everything looks OK my end, however recipients are seeing these issues, and I'm a designer who sends visuals and print files regularly.

Anyone else have this problem, or know of a fix?

Otherwise can anyone else recommend a good free email client that I can run yahoo/gmail through as Mail is unusable in this state now.