You can have both a Traditional and a Roth IRA with IBKR. For 2023, the annual contribution limit is up to $6,500, or $7,500 per year if you are age 50 or older, to any combination of Traditional and Roth IRAs that you have.
The contribution limit for 2022 is up to $6,000, and $7,000 for people age 50 or older.