Newly Vegetarian - Medical Reasons

First off I have no idea what I'm doing. I love cooking and loved doing roasted meats and things like that. And now because of medical reasons(I need to avoid vitamin C). I am told low meat and low salt. At most once a week is all I can do for meat. It's changed my whole life routine with work and conscience with easy options. Not really any fast food options for an easy after work meal.

I know there are lots of impossible beef type things I can buy but if I can get help with the following things. Mainly I am concerned about taste and flavor because most of my cooking used meat as a base for the flavor. Sear off something and deglaze or build other flavors. So is there a difference process to maximize a concentrated flavor in vegetarian cooking? Different methodologies in cooking? Any advice/links to resources would be great.

The other main thing is recipes. Work lunch meals and dinners mainly since I don't do breakfast too often. I like Mexican and Indian a lot but I've been doing some English recipes recently.

I'm not crazy about mushrooms mainly because of the texture being spongey but I'm willing to give it another try.