5 months is closing in on a "retesting" of previous civil behavior and boundaries coupled with the new "feelings" their age might be supplying, perhaps a bit early but....
I know what I have done for the jumping and the biting and I'll suggest an option or two for the jumping. I did it straightforward, pup goes on a dragline immediately and I just stood on the line to restrict the pup's ability to jump but not to the restrict the pup's normal posture. Generally, if you are consistent and patient enough, you'll know when the "extinction burst" occurs. I'd reward the pup when the pup took a calmer position, standing, sitting or downed, it's all the same. If I did it again and the pup's food drive was fairly high, I might try having some food scraps on me and toss them on the floor before the pup started the jumping baloney. Maybe throw a few around as you break the theme the pup started with. If the pup knows the basics, I'd bribe the pup into a sit or down and continue the new behaviors to replace the jumping or other undesirable behaviors with acceptable ones.
I experienced the same as you, ignoring and timeouts didn't work and generally ramped up the pup to bring it on with even more passion so it seemed entirely unproductive.
All the biting stuff I did differently and probably not in a way that might work for you. I allowed the pup to enjoy the desire to work me with her teeth and paws, they do that kind of thing when they are pups, it's kind of how they express themselves at that age ( certainly younger ). I taught bite inhibition and bite pressures through a designated "play" session with a distinct beginning and ending and also provided appropriate outlets besides my forearms and hands, if our sessions weren't in session
It's a lot of fun and few puppy scratches and bites along the way but I like a spirited pup! Like I said, probably not the way you might like to go. But FWIW, it did stop all unwanted nuisance nipping and she acquired a wonderful use of her jaws and uses them appropriately.