This is gonna sound like a troll post but i assure you it is not.
I don’t have a coding background but I’ve used Teams in a lot of workplaces and really only encountered like 2 issues entirely.
Either I got seriously lucky or it was before enshittification.
Why do you yourself dislike it? Is it UI? Performance?
I should also say I use Teams for basic purposes like messaging and uploading files, I literally don’t touch anything else and performance hadn’t been an issue. (Likely because I’ve been given thicc-ass workstations in the past)
If the data isn’t in M365, it can hardly be Microsoft’s fault if the data was stolen.
Personal addresses, Salaries, Leaves, etc. should all be stored in proper HR systems.