Is your son a pitcher or a position player (I am assuming position player since you linked to a Trey Hannam post)? Having just gone through this with my 2024 RHP, numbers definitely matter. If he is a positional player, then 60 time is important to most schools unless he has college level power hitting potential (no one is looking for singles hitters unless they can really run -- low-mid 6s 60 seems to me). EV is important but not everything as kid still needs to be able to put the barrel on the ball. Also arm strength and positional velo, plus pop time if catcher. Other skills also important for catchers such as leadership, receiving, blocking. If a pitcher, then velo number one thing by far that gets you noticed, although not everything. However, if don't meet their velo minimum they are not going to look. Showcases help, but national level ones more than regional IMO, although they are useful to get verified metrics as you note. One thing your son should be doing after he gets verified numbers and video is to make sure he is promoting himself on social media using Flat Ground and other accounts set up to get players free exposure. I can attest from my son's experience that using these can easily get your son seen by 20K or more people for free. If he gets interest in this way, then they will need to see him play in person before they offer. If he is HA (and even if not), should definitely be looking at D3 as well as this division has the largest number of programs and, unlike the D1s, they are still actively recruiting kids. D1 has gotten a lot harder with the advent of the portal.
My 2 cents for what it's worth. Good luck!