You're probably going to want a brake right from the jump, even if it's only for helping with self-spotting impacts/misses... Almost any that's not total garbage will do really, lots of guys dig the PVA Jet Blast and/or Area419 Hellfire, APA Bastards, but if you're on a budget and want to spend a bit less, I've been shooting a VG6 Gamma 7.62 that was like $40 on sale somewhere and it works great and isn't too obnoxious.
Pick a good bipod, don't let the sticker-shock scare you too much: I run a Harris BRMS like a lot of guys and mainly chose it because the Atlas CAL's price tag seemed a little high, but after adding a Pod-Loc (pretty much mandatory with the Harris, already comes equipped on a CAL) and an $70 ADM adapter/mount (the Harris thumb-screw getting loose on you gets old quick) I'm just about at what a CAL costs so...
I think the Howa is a great choice and not just because that's what I have right now: I've honestly been researching ways to shrink my bank account and put together a "better" rifle, but all the 700-pattern actions most of the cool kids run around here are pretty much pointless unless I add a $300 TriggerTech Diamond or else they're not really going to do much for me no matter how fancy they are when my lowly Howa is shooting .3" at 100 and ~1" at 400.
Most gunsmiths won't even bother/offer to bluprint/true a Howa 1500 action because they're usually already machined well enough where it's not worth doing. Order a Gunbloke trigger-spring off eBay for a few bucks to lower the trigger-pull to ~1lb (takes a few weeks coming from Australia), and work up some loads and you'll probably be surprised what your "cheap rifle" can do lol.
IMHO the 2 best things you can do for your rifle is order the ~$10 spring to transform the trigger, and then add weight where you want/need to in order to steady the rifle. Which is why if there's anyway you can cancel the Oryx chassis, you might want to, because while they're nice, they don't give you much for options on adding weight...
Don't underestimate what dialed ammo, a light/crisp trigger, and a heavy/steady rifle can do for you: I was shooting the other day a few bays down from a guy with a ~$4Kish Defiance/Manners setup and he had a pretty shitty look on his face when he asked me what I payed for my lowly Howa/Bravo setup hahaha...