What will be the purpose of 35mm gear in your photography in the future? That's the question you should answer for yourself before considering equipment choices.
The main weight/bulk problem in your kit lies not in the F5 body, but in the three lenses you mention. If you can replace the 80-200 and 300 with one or two lenses (e.g. 85 or 50+105) for your photography, then the resulting kit will already be much smaller and lighter, but still offer the main advantages of an F5-based kit. This is what I do when I want to go light, but still have the F5 as a body (i.e. 20-35, 50/1.4 and 105/2.8 or 180/2.8).
Otherwise, if you want to go really small/lightweight, IMHO there's no way around a 35mm RF, I'd recommend an M Leica and 2-3 lenses. Prerequisite would be that you can get by with having lenses only in the 20-90mm range, where that kind of kit excels. Incidentally, an M3 plus 2-3 lenses is my choice when I want to go really lightweight (the resulting kit weight is about the same as an F5 body alone, and the "bulk" is not worth mentioning).