Wanting to upgrade in the future, any ideas?

Hi! So I have a leopard gecko named eggroll or eggy for short, Hes quite the old guy. Had him for over 2 years i think (ive lost count)

Now I wanna upgrade his tank in the future or soon- and im kinda lost on what to upgrade.

Can yall show your tanks? Maybe give me some ideas? I have a 40 gallon tank (i wish it was bigger but I do not have the funds for that😅). Also mines nkkt bioactive as I dont know how to do that , (also what would the price be if you could give me an estimate).

Im doing alot of research on him. ive done alot before I got him, but I wanna do way more just to be sure hes healthy!

His tank isnt bad just wish to do more! He deserves literally everything

Any tips help🫶