I'd suggest some cheap wood - sometimes you can piece together enough from the scrap pile at a local store for extra cheap - and make a small raised platform. Buy a corrugated roof panel and cut a cheap aluminum gutter down to size.
Bend the gutter in a way that creates a slope and lip to attach to your platform. You now have a 4x4 platform that will use gravity to send all the water into 1 small bucket.
may or may not be worth it for just a 4x4. You can see examples of how i use this for a 4x8, 4x4 and 3x3. If i bought gardent trays it would have been 500-600 dollars or more, lol. Had to use taller legs than initial build for my 4x8 platform, but i'm not trying to win any beauty paegants. The legs are 1/2" shorter every 2'. I use an extra shim at high end to ensure drips go one way.
maintenance of 4 pots isn't so bad, but if you scale up 1-and-done drainage is so much better than having to do each pot individually. Get a pump with float switch and you don't even have to handle the drainage anymore. Also, sitting in its own piss is usually a bad thing for potted plants and really bad for soilless context. The corrugated panels keep nasty runoff away from pots from start to finish.
thos 200 USD 4x4 gardent trays aren't worth it. they are cheap plastic trash with a 100,000% margin. don't give such horrible people money, lol.