One thing to keep in mind is that, unlike 'design rules' like the IOR, PHRF assigns a rating to allow all sorts of sail boats to race in classes where they should have a chance to win by sailing up to their 'rating'.
i.e. there is no such thing as a boat "designed" to this system.
OTOH there are recognizable hull shapes resulting from several older design rules, like MORC, IOR (this varies by version of the IOR you specify) and some others.
So, while you do not have to spend a lot of money to do well in handicap racing, some things like sail shape do need to be more optimal to allow you to grow your skills. Worth remembering is even at the upper levels of club racing you will generally get beat by another skipper and crew that are simply Better at sailing their boat. i.e. skill will usually overcome less efficient sails and deck gear. That's worth remembering when tempted to spend $$ to "buy" your way into trophies.
For general sailing it's best to have good sail shape, anyway. After all, that is what drives the boat and makes sailing fun.
More practice at sail evolutions and helming will get you closer to being competitive, but it will take a season of starts to to begin to get to the finish line with the other boats. (When I was racing a OD small keel boat we were getting about 40 or so starts or more per season, and by the third season were winning trophies in a fleet of about 20 boats.)
Also, regular racing will make you a Much Better sailor and shorten up the general learning curve a lot. The real purpose of "racing" is become a competent sailor, after all. If all that you really need to be happy is a trophy, just buy one and display it on your mantel. Much cheaper. Then you can take up golf.