“Looks to me” (excuse the pun)-- that the real issue is not so much the dim panels in all GA planes, but more generally, due to decreasing eyesight, the need for a brighter screen… that will help with all screen images. (for both MSFS, as well as other windows programs)
Have you considered adjusting your base Video Display , to optimize its brightness, contrast & gamma, to better suit any reductions in your vision = Easy, NO COST solution>
Then again, it may be that you have an Old , dimming Monitor, and another solution might be to get a new, bright ( Higher Nits), LED backlight Monitor. ( but could be costly).
If you think it may be your monitor, maybe go take a look at some of the newer Monitors at your local Computer store, and if you find one you like, SHOP around for the best price (Possibly Online).