I put a new Merc 20HP EFI on my old 14' Lund in Spring 2021. Like you, I just use the boat to fish.
I like that motor. It's quiet, very thrifty with fuel, and enough power. It will push my boat at 23 mph. I have had absolutely no issues with it. I wanted electric start and rope backup as these old shoulders don't do well yanking on a starter rope. But I have tested that backup pull start and it works just great.
Unless budget is really an issue, you might consider a little bit larger motor. Being able to maneuver the boat on a larger lake like Eufala would be easier with a larger motor, especially in windy conditions.
I have no reason to doubt the quality of the smaller motors. The advantage of that smaller motor would be portability and convenience. It has an integrated fuel tank which would save space in your small boat. However, the small integrated tank might need to be supplemented with a can of spare fuel for those days that you are on a larger lake.
I bought my motor at the local BassPro; they're a Merc dealer. If I was buying a smaller motor like the 5HP, I might buy from an online dealer like onlineoutboards.com. There's discussion about the Tohatsu and the Merc being the same motor with different paint. Merc and Tohatsu do have a manufacturing teaming arrangement of some sort, but their 5HP offerings are not equipped exactly the same. Price is a little different, but not substantially so.