I had a food business that went on Uber Eats.... it was a lifeline for us (although still not enough to keep us afloat, but that's another story). From a standing start we were quickly doing anywhere between £1200-£1500 a week across Monday - Saturday. The majority of this was on breakfast items (which wasn't really our core business to be honest) as I think we were lucky that not many places are open and online at that time except perhaps McDonalds and Greggs. I don;t think we'd have got the same level of business if we were a pizza shop competing with 100 other takeaways in the evening.
Note the fees are HIGH - 30%-35% ish of takings. However, there seems to be an acceptance with consumers that they are paying through the nose for convenience and so we loaded some (not all) onto the item cost. I assure you we are not in a wealthy area, and would get shop regulars who would quibble if we increased something by 10p. But then we regularly had ordered for, say, a sausage bacon & egg barm (sandwich/cob/roll...delete based on your region!) that might have been £3.80 in the shop. It was a fiver on UberEats, plus probably £3.50 - £4.00 delivery. People paid it all day long!
The very, VERY odd person questioned why it was more expensive on Uber than in the shop and then when we explained the fees it was just like "fair enough".
We never spent a penny on marketing with them (there are options to, but they weren't overly pushy with it) and they will give you free marketing, e.g. at numerous times they would fund a "buy one get one free" offer on items. Customer would get the BOGOF, but we'd get paid in full for 2 items. I always found it intriguing that there was no limit to the value or quantity on this. We did it with Full English Breakfasts that were £9.95 each.... I did debate getting my mate to order and pay for 1000 breakfasts (that we never made or delivered) and see if Uber paid us out on the other 1000, but decided I didn't want to get kicked off the platform

From what I remember there was very little, if any, cost to sign up. Nor do I think there was a minimum term or a minimum monthly fee if it didn't work. I'd recommend giving it a go, particularly for the breakfast trade when you have little competition. Saturday mornings when people were hungover were always good (in fact we debated having someone in the shop on Sunday mornings when we were closed PURELY to cook stuff to order for Uber Eats, as I reckon we could have taken £250 on a Sunday morning just delivering hangover cures!