Sorry to lurk here because im very interested in this topic but...
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what if the OPs troubles are not caused by chipset neither network card. But pure fact he plays games with unfair netcode preferring high pingers /csgo, valo, MW /.
Logically, he performs better at LTE than at his home fiber. If he adds fake latency to his ftth (around 60ms in csgo, 35ms in valorant to maximize lagcompensation advantage as these values are a sweetspot pings) he will stop being only prefired and feeling behind because he will start being lagcompensated too what he never will be at his low lateny ftth (thats why chinese esport players play with VPN to singapore - to get at least some latency to be able to do open kills just by lagcompensated peeks). So they no more can see you before you see them. Both games (csgo and valo but also MW) have unfair netcode, csgo has 200ms max lagcompensation (thats why backtrack works so fine in csgo), valorant reduced it to 35ms hard limit but the movement is slower here, so its in the end the same - the peeker wins always. I dont play MW, so i dont know the exact value there but its said its present and high too.
Try to make custom server, a server with fair netcode, disable lagcompensation like in cs 1.6 (you need set sv_unlag to 0 or let it at 1 and set sv_maxunlag 0 from default 0.2s so the lagcompensation is zero). Then connect your PC and play with others. Ideally, invite more players to your local LAN. If you will no more suffer from being prefired, problem was definitelly in the netcode.
OR
You can spoof your latency to be the same like at LTE, install a router outside your pc with linux, just any PC with 2 ethernets (1ETH + USB/ETH port), install netem packet, set at outgoing eth0/1 port netem delay 50ms (or more if you want Russlan prefire), and enjoy free kills. You may also use it only at T side so you have peekers advantage when rushing (i do it with my LTE, when switching sides from CT to T, i vote a timeout and switch from cable to LTE so i have easy opens).
Again, if you start getting better and not feeling behind, its not hardware issue but netcode issue. Also mark server quality, for a valid test you need a good server with server variance max. 3ms +-0.x ms and 0.00x var. Otherwise its not a valid test, at trash server (nearly all official ones at csgo, all DM servers except few ones of warmupserver.net and a half of faceit servers) the aim is a coinflip and aim stutters due to bad server performance. Even 5ms sv is bad, i can notice very easy the difference between 5ms sv and 2.5ms sv server. OF course, its easy to notice bad server var too (the last row and last column in net_graph), any var higher than zero point zero zero x or any var unstability result in noticable microlags and aim and movement stuttering. There is also noticable inertia at higher sv or server var, and crosshair tends to keep moving after sidestep or jumps a little off after you stop your mouse and press counterstep and also the sprays are absolutelly wrong with added false horizontal recoil and which shouldnt be there, also the shooting speed is not exactly correct (almost if you have fast reactions, the server quality is crucially limiting, the faster you act the worse results).
Yes and important thing, throttle your connection! MW seems to run best at 3/0.5mbit limit so the opponents cant read your movement so easy, csgo runs fine at 80000 rates and valorant i dont know exactly now but this game seems to be least prone to throttling since they implemented a server sided player movement computing so players can no more trick their outgoing rates to trash their movement for being tough to hit by others. But in csgo and MW the throttling works perfectly. It also removes stuttering by high bandwith usage and reduces jitter and packet skipping.
Its very possible that at LTE/work the game is set to lower bandwith or simpler rendering automatically as it cant handle your home settings.
Then after you do all of this you can make a final verdict.
Im experiencing the same, but i cant tell definitelly a verdict as there are too many variables and this feeling you described i have only occasionally and yes, i feel better or at least not worse K:D and TTK ratio performance at 2mbps hard limited LTE than at my home ftth, what baffles me because the LTE jitters terribly with random rollback lag every few seconds as the ping spikes for 100+ms for a while. Now im installing kali linux and netem at a secondary PC to start to play with fake latency and making some more valid and exact results (LTE at my secondary address with random lags is not very good for that).
One day i will post my verdict of my research and investigation. Using Intel chipset