First, with respect to the IP ownership. Be honest with the company you are joining about your entrepreneurial goals (it’s usually a quality that good managers

First, with respect to the IP ownership. Be honest with the company you are joining about your entrepreneurial goals (it’s usually a quality that good managers like). You may underestimate their willingness to be flexible. Contracts are alway about setting terms, especially for future unknown situations - if you expect a future situation to arise you can set the right terms. Second, being a good developer doesn’t always equate to launching a company. The skills you might use to launch something new might not be your dev skills at all. Understanding a problem/solution/market fit requires lots of skills you won’t get writing software. You can/should do customer research, low fidelity testing, etc. to prove to yourself something is a good idea before jumping into a new venture.