Should I transfer WP pension into an SIPP?

Hi, 26(M), I earn 25k a year and have just under £7000 in my workplace pension (Royal London), I would like more control over my investments option and would like to pop it in the S&P500 (for 10 or so years at least), but RL don’t offer this. I’m thinking about transferring this pot into an SIPP, and might increase my contributions overtime. Could somebody explain any drawbacks to this plan? Also, how often should I transfer over after the initial transfer since my salary contributions and employers will still go into my RL pension. To also add, in case it’s relevant, my company pay 5% and I pay 3% and its salary sacrifice. Thank you.