If you use the slicing tool on photoshop or webtoon export (i think thats the name) on clip you can slice your panels in really small sections then save in high resolution JPEG (since its the smaller size format compared to PNG). The slicing/export tools save each section automatically in one go and don't worry about cutting panels in half, tapas + webtoon sticks them together without any spaces.
My comic is really colourful with lots of shading and text, i sometimes have 25-30 panels but I've never reached the MB limit. The size for each slice for me is 800x1200 and doing that lets me save it in the highest resolution. I'd rather slice in small sections rather than lose any resolution or change my art in anyway.
Edit to add: Are you saving PNG or JPEG? Png file sizes can be huge which would explain why you might reach the MB limit.