Quite a bit of variability in your question.

The amount of fouling really governs the easy although none of it is really that bad.

Comes down to powder choice IMO. Black powder and pyrodex FFG is the most fouling there is.

Modern synthetics are much cleaner shooting, but still will grunge out your rifle after 20-40 shots at the range. Mostly from primer/cap fouling.

Break action modern ML's have a slight advantage to cleaning.

Sidelocks are not difficult by any means. In some cases, they are easier as they are not as intricate.

Takes me about 30-40 minutes to clean and storage a muzzleloader depending on what powder/cap/primer I'm shooting and how many shots I've fired. And if it's a wooden stock model or synthetic. But I am very meticulous.

The 10 minutes and you are clean is really marketing fluff unless you only shoot a couple of times each session.

Cleaning and caring for your ML should be a pride and thoughtful activity. You may find
a model that takes 5-10 minutes more or less, but that really is negligable if you are doing a good job.