it is a very large lake with about 650 miles of shoreline. Depths can be 360’ at its deepest. Most of our time will be spent in coves and not necessarily in the big water.
Full pool is 360'
above sea level , but the lake is nowhere near that deep. You can find some spots 200' deep if you are directly over the "river" on the Lexington side near the dam.
Anchor effectiveness is largely dependent on the makeup of the lake bottom. We have mud. You will be well served with a generic knock off of a Fluke anchor like this
Seachoice Deluxe Anchor . The one I linked is for 25 to 30 foot boats and I recommend that length for a 22 to 25 foot pontoon.
Since you say most of your anchoring will be near shore, I recommend 50' of rode (a fancy name for anchor rope). That anchor and rope length are what I use 95% of the time and we tie up with others in 15' to 25' of water nearly every weekend. No one here tries to anchor out in the middle in 100' or more of water. If you want to hang out in the middle, you just drift.
Be sure to get about 6' of chain to go between your rope and the anchor. I'm not positive, but I think the chain weighs down the arm it attaches to which helps it to set in the lake bottom. I know I didn't used to have any chain and I had difficulty getting the hook to set sometimes.
You can get turnkey kits with the anchor, shackles, chain and rode. That would be a good way to go but I didn't take the time to search one up meeting my recommendations for you online.
Now, there is a technique to anchoring. Idle about 50'
upwind of your desired destination. Make sure the anchor rode is attached to your boat (if you boat long enough, someday you will regret skipping this step), drop or toss the anchor in the water (if you toss, make sure the rope doesn't tangle with the anchor in the air), put the boat in reverse and move slowly backwards until the anchor hooks. The boat will stop. You can tell by watching a reference point on shore. If it doesn't hook, you need to try again.
I have fender covers on my fenders as a consideration for my fiberglass boat friends. I've tied up to boats with paint jobs that cost more than my boat and fender covers protect their paint.
I do have a small box anchor with 100' of rode for extreme conditions, but I usually use it about once a season.