The Onyx is a PITA compared to the 240!
As others have said you only need the star ratchet tool to get to the centre bearing, which is literally in the middle of the hub shell. I’ve had about 6 sets of 240s on various wheels, some are 6 years old, and I’ve only replaced that bearing on one set. Could live with nipping to the LBS to sort that!
Bontrager wheels don’t use 240s (or any other DT hubs) any more, their weights are way off, and they’re a faff to convert to tubeless using their kits. If you’re thinking of going for 240s I’d build as per your spec, the hubs come up on eBay etc periodically for reasonable money.