I would be surprised if someone hasn't done that already. There are some 3.5" & 4.5" tires I'd like to try on my RCS.
I purchased my RCS on a Black Friday sale in 2019 and have over 16K miles on this Pig. It still runs Gr8 and is for sale because I purchased a "New" RCS last spring. It has the 1000W Bafang motor vs the original 750W motor. The Brakes & Shifting Drivetrain were swapped out for "knock-off" Logan & LTWOO branded brakes & shifter respectively. I've swapped both to Tektro HD-E725 4 piston caliper brakes & the Shimano RD-M5120-SGS 10 Spd Derailleur w/ the matching Cassette & Shifter. Also changed the Front Forks to Bolany's found at that Jungle website.
The original RCS was shown and advertised as an Electric Mountain Bike. Thru my history w/ Juiced, I've been Warned a few times to NOT use this Fat Tire E-bike for "off road" use. It has the steering geometry of a Mtn Bike, but it's not suspended well enough to take the weight of this beast on a rough trail. It wasn't stated so in the original Spec Sheet, but the New RCS does state the same warning, Don't use this E-Bike off road. If by "more nimble" you mean for off road trail use, this E-Bike wasn't build for traditional Mountain Bike type of riding, it just won't hold up to the any kind of jarring or rough riding for very long.
Other than that, if you do find someone who has "been there, done that" for the Rims you're looking for, please share it. There are those who've gone to Tubeless & lighter setup's, meaning a whole new Rim, Hub and Build.
Good Luck & Happy Trails !