StepUp allows you to walk up one block height without having to jump up.
This is a client sided mod. I have tested it on both Singleplayer and Multiplayer. If your character cannot walk up blocks on a server with this activated, deactivate or you could get a ban from that server for “hacking”. Press “J” to activate and deactivate the effects ingame. The keybind can be changed in the controls menu.