There are high quality DIY speakers using top end drivers, solid cabinet plans, using competent crossover designs and components. Madisound has a few kits I have been interested in building but I don’t have the need, space, or motivation at the time.
Building your own speakers is a labor of love. You might save some money but in my opinion you build because you enjoy it like any other hobby. I don’t have the design experience to design my own crossovers and it has been a number of years but still enjoy the North Creek Music System Vision Signatures and Okara II nearfield monitors I built. I’m currently looking into ways to refinish then so I can move them into a light controlled home theater. I may just cover them with a black velvet cover or tape.
You can always try building a subwoofer first. They are easier and you can find out if you enjoy the experience. The subwoofer in the background was the first DIY project, The NCM Leviathan 18" in a down firing end table design.