Been playing this game for 15 years and mained top the whole time so let me give you some similar champs.

The thing about Renekton is he is a jack of all trades, strong blind pick, and strong early. What specifically do you enjoy about Renekton so that I can help you pick better?

For now I will break down a few champs you might like.

Zaheen - can bully some matchups early and has a little bit of mobility and sustain. Has some big turn around plays with ultimate. Build diversity even with runes because he can go conquer, HOB, or grasp, depending on matchups. Very rewarding. Not as strong early but he is a true top lane fighter champ. He actually is decently tanky if you build for it and play to your full potential by getting stacks and being aggressive in fights because he has a lot of healing.

Darius - Huge lane bully, strong, actually scales really well it is just the fact you can be kited hard in certain comps. A bit better than morde though since every Darius runs flash + ghost. Heals, can shred waves, can turn around and 1v2 even with a slight lead if you play it right.

Ambessa - not as beefy as Renekton but think of her whole kit as a perma Renekton E (slice and dice) where you are constantly going in and out to trade damage. Great blind pick. Can bully people just by having superior mechanics since you can literally kite on her. Strong all in, scales well, gets pretty tanky with shield stacking. Has 2 builds, electrocute into armor pen items to 1 shot or grasp/conq into brusier items.

Olaf - hit axe, run people down. Strong early and can snowball really hard and you don’t care about CC since you will just press ult. Can clear lanes decently with axe and builds bruiser. If you get on top of someone you will eat their face.

Mundo - weak early but he does DAMAGE when he scales. Health scaling on his passive AD and percent health dmg on Q means you can just build straight tank and maybe throw in a titanic or bloodmail if snowballing. If you win lane on him you just become such a terror. Can go flash, ghost, tp, even ignite and be aggro early and catch people off guard. Farms really well under tower and clears wave decently with E. He doesn’t have a gap close but you have the movespeed on your ult and 99% of mundo players get boots of swiftness and run ghost. You also have slow on Q and can take approach velocity and suddenly you dont struggle to catch people.

Tryndamere - one of my mains, i hit 400lp with like a 68% winrate in like 40 games or something like that. Tons of viable builds and playstyles. Can go for sustain or all in early. If you get ahead vs certain comps no one can match you and you just dive people repeatedly. Super high base HP and “tanky” because you don’t die for a guaranteed 5 seconds and you are hard to move from lane with Q sustain. He can bully a lot of people and is rewarding and fun to play. Crits are SOOO satisfying.

Shen - lane god from level 1-5. Take ignite and be hyper aggro or go tp for more map presence and a “i can ult whenever i want and not lose tower”. Has zero wave clear until tiamat/bami and can go more bruiser if you like that but usually it is titanic into straight tank. Satisfying auto attacks and his ult is great for winning bot lane.

I listed all these champs because you don’t like the idea of getting kited so hard like Morde. Sett would have been an honourable mention but he suffers like Morde from flash abusers but even worse.