Hi! Welcome to Homecoming! First characters can be daunting and wanting to do EVERYTHING on them is tempting. I find that most people who stick around develop altitis in the extreme - and have a specialized character for each task. That said, "do most things" characters are certainly possible and Brutes are probably my favorite AT to do it on, so great choice!
That said, if you want to solo GMs/AVs, you'll need a lot more survivability than this. Hell, if you want to fire farm effectively at +4/x8 you'll need more defense than this (unless you want to pop purples). I'm not super familiar with Psionic Melee, so I don't feel qualified to talk about your damage or whether you'll be able to solo GMs/AVs with the damage output or how the high psi resist of high-level enemy groups will pan out against this, but I wouldn't feel confident being out front taking damage on a character with 12-18% defense and 38-50% resist (except fire, obviously). You made a great choice in picking a -regen summon, though - there are a few ways to get -regen, and I'm not sure I'd want to solo with JUST the pet for it. Picking up a -regen Lore pet will help too, and in a group (like a Hami raid) folks will appreciate every bit of -regen you bring to the table.
General theory is to start by softcapping positional OR typed (usually excepting Psionic) defense, even on a mainly resist-based build. Getting hit means taking damage, but worse it means taking debuffs. Anything with -def will absolutely destroy you, because if it's hitting you 50% of the time at first then after 4-5 hits it's going to be hitting you 95% of the time, and 50% S/L resist will not save you in an ITF!
That said, there are definitely ways to fix it! Right off the bat I notice you took the Gladiator's +3% but not the Steadfast +3%. You seem to have taken defense powers but purely as mules for LotG 7.5s. You also have THREE travel powers. Even if you want to superspeed, fly and teleport, you could drop Afterburner, swap Teleport for Mystic Flight, drop Fly, and then drop Vengeance to grab Boxing, Toughness, and Weave. Toughness will boost your S/L resist and Weave is great for defense and will replace your Vengeance for a LotG slot, and all you'll really lose is Afterburner and Vengeance (I honestly have never actually popped Vengeance even on characters who have it).
A better choice would probably be to commit to just one travel power, in my opinion (and not Mystic Flight unless you want other things in Sorcery - it's a good pool but probably not for this character). I usually don't like to HoverBrute, I much prefer a Combat Jumping Brute with Superspeed since Jump Packs and P2W flight exists for vertical traversal when I need it, but this is all preference.
You're leaving a lot of damage on the table by not taking Concentration. I only ever skip my Build Up type power if it would take me over damage cap at full Fury, and usually not even then - you're sitting at 484% at max Fury so you've got plenty of room to benefit from it. Your build will be pretty end hungry (an Ageless Destiny could help), so I'm not sure I'd want to play it without Consume. You've got plenty of Fire Damage but I'd still almost never skip Mass Levitate - it's a ton of damage and a very short recharge for what it does. You could get it down to six seconds and it's pure Smashing damage, juggling psi-resistant packs like Carnival with Mass Levitate while they die in your Burn patch and Blazing Aura sounds like how I'd tackle that problem, but you've left it untaken. Once you've got survivability taken care of, you probably won't need Rise of the Phoenix - but I get taking it. I almost always take my self-rez if I'm on a character with one available just in case I have an ADHD moment, my dog does something cute, I get distracted, and unalive myself.
With a bit of slotting for Defense, some power swaps, some slot rearrangement to get your defense powers slotted, maybe an Alpha Agility? This could be a good trash-clearing tank for general content or a farmer - and not just fire farming but any kind of farming. Fire farming is only called fire farming because you build a SPECIFIC character for it that only needs to softcap fire and get some fire resist; being able to farm good farming missions can be better than AE for a general content character, since you can get merits as well as you go, either for Incarnate progression, getting stuff you need for your build, or just spamming out Converters to sell. (Each reward merit -> 3 converters -> 210k inf on top of whatever else you were doing.)
I know this was rambly and long but I hope there was at least something good to take away in it! Good luck and I hope you have fun!
