I would like to move into to product and to be able to prove my skills as a PM I want to start working on a side project.
I already have an awesome idea and I am looking for people who are in a similar situation (looking to do a career change) and want to work on this project with me.
I am looking for a Designer & Developer who want to prove their skills, work on a creative project and maybe even turn the idea into a startup.
Do you have a recommendation for a platform specialised for people who look to connect for a project?
Nope. Designers/Developers don't generally work on spec. They have no need to prove their skills. They're in-demand all the time. So, the answer is to just hire one. But, do NOT hire one until you have completed your research, developed a marketing strategy, validated that strategy, and let your marketing findings define the product you will develop.
Starting with design is wrong and will lead to enormous waste.
Look at the kind of risk you're asking someone else to take. If you haven't done anything to reduce the risk to an acceptable level, no one will join you. Developers aren't sitting out there looking for things to explore "for fun" or for hope of a future reward.