Can I just not equip certain weapons

[Viper]

My Sentinal seems like he can only equip axes and 1 handed swords. The option to equip is greyed out for 2 handed swords for example.

[Twogs]

Sentinel can definitely use 2 handed swords.

Guess you are not fulfilling another requirement

[Karnaij]

do you have something in your offhand if you do take it off aswell
otherwise check the level required all classes can use all weapons

[Viper]

Do I have to remove my shield first...Which is kind of dumb that the game does not just do it for you if you want to equip a 2 handed weapon.

[Espio0]

Check the level requirement in the bottom right corner.

[Grimmay]

yup you HAVE to take off both the 1h and Shield to do it