First, most lender lender don't FICO 8, we now use EFX 5, TU 4, EXP 2). There is no such thing as "There is no way to raise your scores". Impossible! Over the years I have found several credit cards companies that will approve 100% of applicants for a secured card which can potentially raise your score 20-35 points in a relatively short time frame. Some can rate in 30 days and as early as 2 weeks. That aside, if you are in a time crunch, you may have to go with what you have now. While many lenders require a 580 middle score, some us lenders go down to 550 on FHA at 96.5% LTV.
Best wishes to you!