I would like to replace some outlets that run along my kitchen countertop because the TRR plugs are hard to plug in, and I would like to put ones that have USB jacks. I know that GFCIs are required in this area, but if I install dual GFCI/AFCIs breaker to support this circuit and replace it with the non-CI USB outlets, would this be to code? Is there any easy way I could have found out if this was to code myself (I assume reading NEC 20, is the start?), or is this a bad idea for a DIYer? Thanks!
You're not on NEC 2020 yet, unless your state just adopted it. (MA has so far).
Under NEC 2017, Code requires GFCI only in certain places (kitchen being one of those) and it generally does not require AFCI breakers in those places. The rationale being that providing both can be a technical challenge. So you probably do not require AFCI protection in the wiring to a kitchen, but it is a good idea if (in order of importance) roached wiring, aluminum wiring, old wiring, or wiring in non-metallic cabling or conduit. IMO.
Keep in mind despite the similar names, AFCI and GFCI do totally different things. AFCI protects wiring from burnup due to bad connections, and this mainly guards in-wall wiring, particularly backstab connections. Originally they were conceived to protect electric blankets, but "backstabs in plastic boxes" proved to be the main thing AFCIs defend from. Whereas GFCI protects humans from shock, hence the requirement anywhere within reach of a sink.
AFCI is only constructive at the breaker. GFCI can be anywhere, however. And at the breaker is just fine. Your plan is perfectly fine.
Keep in mind that making an outlet USB does not erase any requirement for Tamper Resistance. If TR is a requirement, then you need a recep that is TR and USB. There is a lot of junk on sale on Amazon Marketplace and other outlets of the Alibaba junkstream, which uses direct mail to circumvent the laws which assure the supply chain contains safe, UL-listed products. Such things are best bought at a bricks-and-mortar retailer; if you don't like Home Depot's pricing, try a genuine electrical supply.
Do your level best to keep refrigerators, freezers, fire alarms, radon systems and other "needs power for safety" appliances away from both GFCI and AFCI.
You could swap out the breaker for a GFCI/AFCI breaker but then if it trips you have to go to the panel to reset it. You could use a dual function (GFCI and AFCI) outlet that are not tamper resistant, to replace the existing ones, but that isn't code now. TRR are required. I don't know of a dual function outlet with USB, but you could put a non protected outlet with USB ports downstream of the GFCI/AFCI outlets. Just be sure they are indeed protected by the upstream outlets. You can easily test this by pressing the test button on your existing outlets and see which other outlets no longer have power.
According to National Electric Code 210.8(A)(6):
125-volt, single-phase, 15- and 20-ampere receptacles that serve countertop surfaces shall have ground-fault circuit-interrupter protection for personnel. [NEC 210.8(A)(6)]
ground-fault circuit-interrupter protection? It is either a GFCI outlet or a GFCI breaker:
GROUND-FAULT CIRCUIT-INTERRUPTER A device intended for the protection of personnel that functions to deenergize a circuit or portion thereof within an established period of time when a current to ground exceeds the value for a Class A device. [2017 Florida Building Code Ch. 35 ... NEC Citation needed]
So using a GFCI breaker is appropriate. Code does NOT state that an AFCI is required for the countertops, so using a dual GFCI/AFCI is just as acceptable as a regular GFCI breaker. Whatever receptacle outlets (your USB plugs) you decide to put in, well that's whatever you choose. As far as NEC code, you're compliant.