If you are weaker on the FE side from a project point of view keep your 'stack' really small, jQuery and Vue.js would get you a long way without really needing

If you are weaker on the FE side from a project point of view keep your 'stack' really small, jQuery and Vue.js would get you a long way without really needing much front end knowledge, you can then gradually add in the other tools as you go (things like SASS/Less etc).