When I am vocalizing from middle C onwards, around E4, F4 (passagio) onwards up to C5 I always sound "strangled" when I try to sing within that range with "full voice". I have been practicing head voice within that range, and that sound fine, but when I try to sing in more of a "chest dominant mix" or in a broadway belting style within that range, I just sounded so strained and sometimes the voice just cracked. I have a comparatively weaker breath support but I've been working hard to improve my support. I put in all effort I have, lower abdominal, rib cage all 360 degree breath support and whatever I could, also trying to stay "grounded" as I sing, but why do I still strain so much?
I'm not a vocal coach, but my understanding is that, if you are 'straining' or trying to force things at all to reach a particular note, then you are probably doing something wrong (and may risk damaging your voice in the longer term). The advice about finding a professional coach is probably a good idea.
In terms of specific advice (from my own experience): as you increase in pitch in chest voice, you will always reach a point where you start struggling and the sound starts to become 'strangled' (as you put it). This is where switching to head voice will alleviate that tension, and enable you to get to higher notes, but the 'pure' head voice won't be as strong and full as your chest voice.
As I understand it, one goal of singing training is to 'smooth out' that transition between chest and head voice (i.e. the passagio), to create a smoother, more blended range, where in the middle you have a 'mix' of chest and head voice. Doing that should allow you to get some percentage of chest voice tone at higher pitches than you could previously, but the 'mix' will still have to lean more and more towards head voice, the higher you go.
I believe the amount of chest voice mix you can achieve a particular pitch can be increased with practice and training. But, doing that is going to be a gradual process that will take time and, as I said above, if you try to force or strain it, you might risk damaging your voice over the longer term. Best option is probably to find a coach, if you can afford it.
IF it sounds strangled, it's likely you're pulling up chest voice, that is, singing higher than you should be singing at this time. Can you hit those notes in head voice comfortably , without sounding strangled? If so, you're probably pulling up chest voice. I would second the idea that perhaps you should work with a voice coach, because if you ARE pulling up chest voice , that WILL damage your voice.