4K video can definitely be a pain to edit (I have a very fast HP workstation with a pair of 6 core 3.7 Ghz Intel Xeon processors and twin Nvidia workstation graphics cards and video editing with 4K still seems sluggish at times). Capturing in HD will work fine BUT you need to have a combination of lens focal length and distance from the keep so that you have a good view of the actions of the opponents and her defenders that is driving her decision making and actions. Leaping saves make great highlights but key goalie skills include placement, great decision making on when to cover the ball or kick it away, how well she recovers from a blocked attempt in order to stop a followup shot on goal, etc. Be really careful with video editing not to edit out the context which is what the coaches need to assess her skills, athleticism, and critical decision making.
The angle is critical for the same reason and you want to be positioned far enough downfield to provide a good view of the action leading up to your daughter's reactions and that makes focal length important because getting the proper angle to capture the relevant lead in to action involving the keep means being farther downfield than you would be if just trying to capture athleticism highlights.
Most DSLR and mirrorless "still" cameras that double as video cameras will have fairly tight limits for sustained video shooting so most of them won't allow you to shoot a continuous 40 minute half without pause. Even those that don't impose a strict time limit (i.e. 29 minutes like a lot of cameras that were designed to avoid the EU "video camera" tax) will have heat management issues when shooting sustained video clips and that is particularly true when shooting in the sun on a hot late spring afternoon. Battery life is also a consideration as to how long it will shoot without changing batteries.
My daughter is likely to play college soccer also but she is going via an academic rather than athletic scholarship so it is a different situation however I still captured video. I much prefer shooting stills and I have sidelines access via the team for doing this photography. A couple of JV players volunteered to take care of video for my daughter so I set up my camcorder on a tripod so that I could continue to do the photography I prefer. No matter what you use, you will want to use a tripod because the coaches don't want to watch the soccer version of the Blair Witch Project with the image constantly bouncing.
Bottom line, the camera equipment is important but be sure you capture and edit video from her potential college coaches' point of view and not just the ending highlights of an attack on goal. The coaches can't truly assess her playing ability and decision making without seeing what she is seeing including how well she functions as a unit with her defensive line (in my view during the game a good keep "owns" her defensive players because she has an even better view than the coach of what is happening in the box and a great keep is also great at managing her defenders).
Good luck to your daughter!
Rodger
EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video
