Can I solo Gengar with shadow ball?

Nope Exeggutor is weak to Shadow Ball.

You can use Snorlax with Lick/Earthquake, or to say (probably) Snorlax's worst moveset, if you want to use as an anchor.

Did you dodge with the Tyranitars? If you did, you should not. Tyra wants to tank everything that isn't Focus Blast to generate energy.

Go with Espeons and Alakazams first, followed by 2-3 Tyra. This is generally what you should do in any solo raid, highest DPS first, tanks last. You should be able to pull it off if the whole team is at least level 30.

Gengar can be tricky. Sometimes I win with 30 seconds left, and sometimes I fail. I still haven't figured out how to distinguish hex from sucker punch, because the animations look pretty much identical to me.

With that said, I think SB Gengar is within your capability. Those T-tars are key, especially the B/C ones. You'll want to make sure they're powered up to their final breakpoint for bite. That is level 32.5 for an attack IV of 15, and one half level higher for every point that the attack IV is less than 15.

An Exeggutor might be useful, but you haven't given any information about what Eggys you have available. Confusion/psychic would be good; solar beam is resisted by Gengar's poison typing. Alakazam and Espeon aren't very good against SB. Do you have any double dark Houndooms?

Don't try to heal. Your goal should be to do enough damage with your first six that you can mop up with the auto-select lineup. Or better yet, kill the Gengar soon enough that your first six are all you need. And err on the side of dodging less, not more. But one extra FS from Alakazam or Espeon can make the difference. Good luck.

How much damage and time remains when your last TTAR dies? Might be worth running out to heal them instead of using so-so options. Just a thought. Good luck!

I've had that same trouble with shadow ball Gengar. I would say start with espeon, alakazam, and a shadow ball gengar. Then the B/SE Ttar, then the B/C Ttars. Try to get 1-2 charges off (2 would be ideal but requires very good dodging) with the glass cannons. Then no dodging with the ttars. Other options to try are swapping out a glass cannon for a Dragonite if dodging is an issue. I think the key is adding a gengar or maybe 2 though. His dps is through the roof.

Alakazam, Espeon, Gengar are still your best friend for defeating Gengar..
Shadow ball is easy to dodge, just wait a bit when the ball start to launch, then dodge. Have to learn it first, but when you have the hang of it, it become more and more easy..
Try atleast fire your mon's CM twice, and try to dodge all boss CM if you can..
Than one TTar (or 2 if you choose to play more safely) in the last position. Dodge only if you have to with TTar..
All your attacker at level 31-32 is good enough, higher level will make the job easier...
Off course you can use 6 B/C high level TTar for beating Gengar, but that's no fun, and actually slower than using the glass cannon trio..

I can’t remember if it was vs Machamp or Gengar but I think Espeon has a confusion breakpoint at level 30.5-32 (depending on att stat).