Saying someone is running "too many" mods is purely an opinion. Use as many as you find useful and/or amusing, assuming your computer can handle the load. I think I'm running about 115 in the current 1.10.2 instance I'm playing. As for the keybinding issue, you could try Mine Menu if you're playing a version of MC for which it's available - I haven't actually tried it yet, but it sounds promising.
Aside from that, what I usually do is try to determine which key binds are most necessary, i.e., ones that perform functions I may need to access quickly (jetpack controls, for example, in case a speedy escape is warranted) and ones that trigger something that has no alternate means of access, such as the main menu for Psi, and set those keybindings first. Then I prioritize others by usefulness and level of redundancy (many key binds trigger an action that can be accomplished in another way, such as opening a backpack by right clicking while holding it, or setting a waypoint from within the main JourneyMap GUI), and assign the remaining keys to the functions I'll use most often. The key binds I find unnecessary I set to "NONE" (using the esc key) to avoid conflicts. As another example, Chisels & Bits lists 15 or more possible key binds, one for each action you can perform with the chisel - of these, I only use 2: 1 for the radial menu, from which you can access all chisel functions, and 1 for "undo".
Play around with each mod as you add them and try to assess how important the key binds it wants to add would be to the way you play, then assign them in order of preference until you run out of keys. And don't forget about frequently overlooked keys, like "0" (zero), punctuation keys, and unassigned function keys. Also keep in mind that nothing is set in stone - you can always change, activate, or deactivate keybindings as you figure out what works best for you.
Thank you , that was very helpful