Secured card or credit-builder loan after foreclosure?

My foreclosure was completed about 18 months ago, and my scores are currently in the 610–630 range. I have one open credit card with a $500 limit and a $90 balance, no missed payments since the foreclosure, and no other active installment accounts. I can set aside about $500 for a deposit, or roughly $35–$50 per month if a loan would be more useful.

I’m trying to choose the option that best supports mortgage readiness over the next two to three years. A secured card would give me flexible access to revolving credit, but I’d need to keep the balance very low so utilization doesn’t hurt my scores. A credit-builder loan would create a fixed monthly payment and add installment history, though the money would be tied up until the loan ends.

For those who’ve evaluated both after foreclosure, which factor mattered more in practice: keeping revolving utilization low with a secured card, or adding consistent installment payments with a credit-builder loan? Would one be preferable with my existing $500 card, or is using both likely to create more monthly obligations than the scoring benefit is worth?