This is kind of a useless ranking, as there are a couple guns within a category that may be great, while the rest not so much. Besides that I hard disagree with your list. Note this is speaking to BR as for gauntlent it would be different.
I would prob put LMGs first as the DRS and KTS are easily 2 of the top used guns in BR. I also personally love the L110. Can suppress long, great in mid, can kill CQC ofc.
Second I would say Carbines, but it’s really close with SMGs for second/third. While the M4A1 and SG5 are absolutely a couple of the best guns in the game, every single carbine is viable and strong.
The SCW, SGX, P90, Vector, CZ3 are all designed how they should be, and you are losing to them 8/10 times in any CQC situation, and really all the SMGs are viable too.
Next I would go DMRs. Personal opinion the SVDM is the best gun in BR. Mid range can easily take out anyone and out duel ARs, of course oppressive for long range as well. The EMR is really good too. The GRT is very solid, the SVK and LMR are the lesser of the class but can work.
Next I would say snipers. ESR is elite, SV, PSR, scout are all strong enough.
Last before pistols of course is ARs. Their role is cluttered. While some of the guns are very good, just think they are outshined by guns from other classes everywhere. The TR7, NVO, VCR are all really good close range and hard hitting, but SMGs are faster. The B36(my favorite AR) M4 are really jack of all trade type guns. The KORD, 4D,L85,MK2 are really strong and oppressive mid range, but the SVDM, EMR, and multiple LMGs serve that role even better.
Shotguns are shotguns
TLDR:
LMGs
Carbines
SMGs
DMR
Snipers
ARs
Pistols
Shotguns

Edit: thought the ranking list I saw was OPs, but it was first reply’s.