heres what I would recommend you do with the intent being to focus your gamplay and make you more effective.
you want to fully elite one chassis of every weight class. the difference between elited is like comparing a non basiced mech to a fully basiced mech all over again, its pretty huge.
the fastest way for you to do this is to pick up a catapult C1 and a third blackjack. once you basic these mechs it will open up the elite skills for all variants that you have basiced. once you have fully elited all three variants it will then open up the extra module slot and give you the x2 basics. you wont have to fully elite all three variants of that weight class to access this in the future.
i would then work on a light and an assault. if you like ravens they are a good choice, the 3l, huggin, 2x are all great versatile mechs.
for assaults you seem interested in king crabs and i would highly recommend them based on your interests. they are slow, however they are highly maneuverable (they have perks to boost their yaw speed and have a wider FOV compared to a direwolf and are the only mechs in the game that can match their firepower).
i would NOT put an XL in a crab, but there are tons of builds you can pick from, all 3 variants are good although i prefer the 4x UAC5 in my 000L.
once you have that done you will have at least 3 variants of a chassis from each weight class and from there you can start experimenting with timbers, jagers, and others.
start spending your pilot XP on usefull skill unlocks (improved uav, uav upgrade, siesmic sensor, radar deprivation) and start saving cbills to buy the good mech modules, these would be siesmic sensor, radar deprivation, possibly target decay. usefull weapon modules are kind of a luxury as they require a large amount of time cbills and gxp to aquire so start with the mech modules, they can be used on anything.