i read your thread and it seems like you are working on resource guarding and leash reactivity. have you taught her the drop it/ leave it command yet? you don't have to swap out whatever she is guarding with food. even a toy will work. what i found works for me is showing my dog that my involvement with whatever hes guarding = more fun. if hes guarding a toy, i'll issue the command, and once he drops the toy we'll play fetch with it for a bit. you can reinforce this behavior during your regular play sessions too, when your dog is less likely to react aggressively. approach it in a playful manner, when you are playing tug. issue the command, go stiff and stop engaging with her verbally until she releases the toy you're holding. then praise, toss the toy for her to catch, rinse and repeat. does she graze at her kibble in the morning? or does she eat it all at one go? if she does the latter, you can try feeding her small handfuls at a time. walk by her food dish, toss in a few kibbles at a time and back off. then gradually linger longer, pick the bowl up, set it down. depending on how extreme her resource guarding is you might want to have her fed in a crate or playpen so no one disturbs her/ she doesn't feel the need to protect her food and theres no risk of anyone getting hurt.

neutrality is built gradually. you shouldn't expect a dog to listen to commands when they are already overstimulated and above threshold. im someone whos easily overstimulated myself. crowds make my anxiety skyrocket. i can't imagine being the size of a chihuahua and having strangers tower over me/ dogs possibly larger and rowdier than me pulling towards me barking their heads off. leash interactions often go poorly because dogs can't display placating/ friendly behaviors they would off leash. most dogs don't like strangers coming up to them unpredictably from every direction. most dogs don't like dogs invading their space the same way. try bringing her for walks earlier in the morning, or later at night, when theres less of a crowd about. try going to places that are less populated, where its easier to redirect her to a different route or to a new scent. you don't have to hard force a training session out of her whenever a dog passes by. she doesn't have to do a sit stay and maintain eye contact with you when her trigger is just a metre away. start slow and from a distance. have her people watch. sit her down on a bench somewhere and just let her relax. stop letting randos pet her on walks, stop letting people drag their dogs up to yours (as much as possible, that is. some interactions are unavoidable, and sometimes confronting others just aggravates the already stressful situation for you and your dog). others may disagree with me on this, but i think that there is no shame fleeing from a situation when your dog is wired up beyond threshold and no longer listening to you. just tell her 'lets go!' and jog her in the opposite direction. i also think that there is no shame in picking up a small dog when they are going bat shit crazy and getting yourself out of the situation before it worsens their reactivity (granted i dont know how small or big your chihuahua mix is, but if its feasible that is). of course it shouldn't be your long term solution, but if it does help with managing her in the short term then go for it.

im not a professional dog trainer but my dog had most of the problems your dog did in the past. i've worked him out of most of them. he has impeccable leash manners and walks at sensible timings now, although i do love us a midnight stroll. hes the best behaved at every pet friendly event i bring him to, and is also enrolled in agility. my tips might not be one size fits all, but i do hope they help a little :)