By switching to a mech keyboard leave you will indeed have more choice in the switches (more or less hardness, tactile versus linear, etc. ), which can indeed help preserving your fingers.

However, most causes of pain are due to other factors:

• the way you sit (in particular related height wrt keyboard and screen)
• mouse (type of mouse, position wrt keyboard, … )
• the frequency of pauses at work
• keyboard physical layout (less keys, with better placement, means less effort)

Since we are in a ergo keyboard community, naturally we would like to address the last factor in this list and suggest you small split keyboards with columnar layout (many examples in other posts, I will not cite any here!).

Such keyboards would make a much bigger difference than other suggestions already made in other answers to your post (which look too similar to your current keyboard), but they require some effort learning new habits.

Anyway, don’t neglect the other factors in the list: use an ergo chair, prefer a trackball to a regular mouse, keep it close to your typing position (easier with a small keyboard, or with a split, if the trackball is between halves), …