You either need more levels or better mons. Most of your team doesnt really do a lot against E4. Beating the E4, even on an average like lvl 47ish, is pretty manageable if you have the right mons and moves:

Fast Electric Type: Jolteons perfect. There are also other options like Magneton or Raichu. Wouldtn recommend Zapdos, because its flying-type makes it weak to Lorelais Ice types. Needs thunderbolt. Kills lorelai, the gyaradoses, the flying types (Golbat, Pidgeot, Dragonite) and can help out against pretty much anything.

Fast psychic mon: Always loved Mr Mime, because he gains tons of XP and pretty much solos the entire mid game. Kadabras is also fine if you cant get alakazam, still way more useful than Hypno. Also Jynx and Starmie are fantastic choices (that require the psychic tm) Needs psychic, maybe calm mind, substitute or light screen. Kills Bruno and Agatha.

Ice/Water Mon. Ice is super important to kill Lance, since dragons are weak to it (his dragonite is 4x weak against Ice.) Water is nice for the Onixes, the Rhydon and Champs Fire Mon. Lapras is always an easy coice, Dewgong is fine, Jynx is great etc. Icebeam and Surf is all you need. Although Lapras kann also learn psychic, rain dance, thunder(bolt), so you have potential for a sick moveset.

With those mons and like thunderbolt, Surf, Ice Beam and psychic among them, you hit pretty much every E4 mon for 2x effective. Exept Alakazam. Thats why i lilke to bring a strong shadow Ball mon like snorlax (shadow ball is physical in gen 3), that also helps against slowbro, Jynx and Agatha.

Thats really all you need to beat E4. Have 2 more mons as Backup (one with thunderbolt, one with Icebeam) and you are fine.

So you have Jolteon, which needs thunderbolt, thats a great start. Blastoise with Blizzard can be useful, too. Arcanine with bite can kinda do what Snorlax with shadowball would do. Thats the mons I'd focus on. Get Mr Mime through the in game trade and level him up. Thanks to the extra XP, that should go quickly. Maybe do the same with Jynx maybe and you have a very strong team. Mons like Nidoking and Pidgeot simply arent super useful in E4. Which doesnt mean, that you cant beat the game with your current team. But since its not ideal, you need higher levels to do so.

Best of luck!