the default mastercomfig recommended are good ones to have:
-novid -nojoy -nosteamcontroller -nohltv -particles 1 -precachefontchars -noquicktime
(others that you could set can be found here: https://docs.mastercomfig.com/latest/customization/launch_options/, if you're considering the -dxlevel launch option then make sure to only set it for one game start and remove it after that)
#What are the best set of launch options I should be using to maximize fps?
boreal iron
and no there's no way to prevent fps drops while in combat in a full server, your fps will naturally go down as there's just so much to process (and it doesn't help that tf2's not particularly efficient at processing that stuff either)
most you can do is minimize that fps drop, if you have mastercomfig installed then that's probably the best you can do--launch options won't really help you there much; you could consider applying some OS optimizations (not everything will be applicable to you): https://docs.mastercomfig.com/latest/os/windows/
ruby storm
can't find nahimic service
boreal iron
yeah not all of those optimizations are applicable to you
if you don't find it then you might not have it
ruby storm
o
boreal iron
yea those are just an assortment of things that you could do if you have it, not all universal things