Solo queue
In a solo order the specialist plays on the account. It usually requires account access and therefore carries more account-security and enforcement risk. Use unique temporary credentials and change them after delivery.
- Often faster to schedule
- Requires account access
- Less opportunity to learn during the games
Duo queue
In duo queue you keep control of your account and play alongside the specialist. It can be easier to observe decisions and ask questions, but matching ranks, regions and schedules may extend the wait.
Coaching
If your priority is durable improvement or avoiding credential sharing, coaching is the clearest option. A good session finishes with a small number of repeatable drills and priorities, not a vague list of mistakes.