Hmmm you have a good type matchup and items are set but moveset is your BIG problem and you being quite low level for the part of the game. Level 24 or higher would have been better, level 30 at that point? I don’t think so… that would make it a lot easier but I have seen people get past the whole game while level 20s :)
Marriland’s walkthrough is one of them, he completed the game without being high level.
Your moveset is terrible however, you need powerful moves now! Fire spin sucks, still know tackle at this point? Razor leaf is fine, mega drain should be around the corner for Turtwig, they are bulky in Hp so they are useful. Sand tomb is pretty useful I guess, until you get TM Dig or another move strong than sand tomb, good for taking out electric types. Low kick is good for know, why do you STILL know growl? Could’ve taught yourself Attract which is the first TM you get in the game, I got it and taught a friendly Vulpix cuz me nor my partner are female (surprising isn’t it?)…
I am Riolu, not the best in defense or HP but attack is high and comes with Vaccum Wave and Bite, psychic and ghost weakness is covered and vaccum wave hits from afar…
My partner is Froakie. It knows Aerial Ace, a move that never misses and covers his grass weakness, also knows bubble, quick attack and lick for now. I am only level 15 and just got to the ghost story in the school part
Vulpix might not be as fast but it covers bug and grass types pretty well and it knows quick attack too :)
Did you know you can manually choose your partner? Yeah it automatically does it for you but you can just say no and pick it yourself, it originally picked Chespin which isn’t that great and plus 2 pokemon weak to flying types? Bad idea! So I chose Froakie, yeah you would have said Pikachu would be more suitable but…Pikachu is overrated and actually pretty weak for most of the game until it reaches higher levels, like 40 ish… yeah. That has been my experience with it…
Riolu and Froakie to the rescue! Yeah! These 2 are quite fast as well, I have Vulpix on me cuz it is same level as me and it knows Attract which is rather handy in this game, has been in previous mystery dungeon games at least.
You need to teach yourself better moves and level up a little bit at least then you are set! :)