Almost all brands have a 5-7" screen fish finder with GPS. They're all good, but picking the one that's "good enough" for you depends on your needs - and the size of the bank you're trying not to break. I like Humminbird, but in honesty Lowrance, Garmin, and RayMarine are just as good. Fans of each would say better.
I'll be the first to admit that I don't have a ton of experience with fishfinders like some of the guys. I did enough research to get a basic idea of what I wanted, then decided to jump in to get a feel for what I actually liked/disliked. I wanted matching units at the console and in the bow for the trolling motor but didn't want to break the bank with high-dollar units. I ended up with these and am happy so far, though Covid put the brakes on using them as much as I would have liked. Looks like they're out of stock here, but it's a good reference point if nothing else.
I had a Lowrance Hook 2 7-inch. When I’m GPS mode, it didn’t update real-time. More like once every 1/4 mile when underway. It would lose the bottom if going more than about 15kts. I’ve had much better luck with HDS units.
I am still back in the dark ages (imagine that!) of DEPTH finders. We tend to catch more fish in spots where the device indicates changes in the bottom than we do in places where little fishies appear on the screen.
I have a hook 2 and it shows what is under the boat. Easy to see fish and will show your lure no problem. You can turn on fish ID and it will show depictions of the fish and depth. I also have a Garmin UHD 9" screen. It is easier to use. Shows very detailed images with the imaging. Big fish you can tell which end is the head and the tail. Mapping and charting is easy and intuitive. Humminbird is supposed to be even better images, but cost more. i figure most any 300 dollar current unit would work. The technology has changed a lot since I bought my last one 10 years ago.
I am still back in the dark ages (imagine that!) of DEPTH finders. We tend to catch more fish in spots where the device indicates changes in the bottom than we do in places where little fishies appear on the screen.
I’m in the same boat taught how to walleye fish by structure not fish looking things on screen
humminbird hands down. I have 3 of them (2 currently on boat) I have a helix 12" with side imaging at the helm, and a 7" on the bow. I love them. if you're looking for a good used unit, I have a helix 5 DI with mapping that ill sell cheap, its not doing me any good.