I've had good luck making rain pants using Green Pepper pattern F578, which is now #128. I leave out the leg zippers to save a little weight. They also have a rain suit pattern that may include the same pants (#134).

https://www.thegreenpepper.com/wp-content/uploads/2013/11/128-web.pdf

The pants are easy. The jacket would be more difficult and time consuming.

I haven't used them, but the Frog Toggs Extremelite series looks better than the original Frog Toggs in both fit and durability. I've seen them in a store, and they seem better, at least. A little more expensive, but still much cheaper than most.

I gave up trying to re-seal an old Marmot rain jacket, but it was pretty far gone, with the w/b coating peeling off. Small sections of the seam tape could be repaired with Seam Grip, if the rest of it is still adhering well.