i walked to the corner store without a mask on the other day and this dude in a pickup truck started driving towards me like he was gonna hit me and mouthed the words "put on a mask!" which i thought was pretty funny because he wasn't wearing one either.
if you want to grow muscle you need carbs and unwashed white rice with all that gooey starch is one of the best carbs to eat to do it. insulin spikes are required to get nutrients into your muscles. maybe people in the 70's weren't as fat because portions were not made into super-sizes yet, no one was sitting on a computer or couch all day and kids still played outside, lol
get a pullup bar you can put in a doorway too, they're pretty cheap, just make sure it can support your weight. also, look up how to do them correctly and learn all the variations from calisthenics videos, you will make crazy upper body progress being a heavy person. you will be sore as fuck the first few times you use it, don't get discouraged. lookup isometric pull-up hold routines to get stronger if you can't do a pullup on day 1.
good pullup form video: https://www.youtube.com/watch?v=K81-SLUFo9c
good dumbbell routine video: https://www.youtube.com/watch?v=y1r9toPQNkM
do not put off doing other bodyweight exercises. calisthenics are your friend for losing weight and putting on lean muscle mass. they are good compound exercises. use dumbbells to target muscles that aren't getting enough attention.
once you get used to your routine with pullups and dumbbells look into getting a barbell (or gym membership) and this book "Starting Strength: Basic Barbell Training, 3rd Edition by Mark Rippeto" to learn how to use it properly without hurting yourself.
despite what most people say, you can grow muscle and lose fat at the same time, there is no reason to 'bulk' or 'cut' you just need to optimize your diet.
here's a good video on that: https://www.youtube.com/watch?v=Bz3AG-oCXTE
i recommend watching all of his videos, especially the ones on nutrition, which sounds like something you are looking for answers to. it's a lot to take in so take notes if you need to.
nutrition video playlist: https://www.youtube.com/watch?v=2SZ3B3Tqvh4&list=PLWfeb0tY28BoaEpuF9cPslnOlSjIh9jfs
get a big tub of whey protein isolate or concentrate and try to get around 150g of protein per day to start, mostly from meats. supplement with whey to save time, money, and calories. protein bars have way more calories to protein than shakes, but do make a good snack when you want something sweet or need protein on the go. you do not need 1g+ protein per 1lb of body weight in the beginning (or at all depending on goals) but do increase protein consumption as you grow more muscle and make progress.
i do not recommend doing keto, unless you absolutely need to lose weight as fast as possible. it shouldn't be a long term diet plan unless you have diabetes, i do know someone who cured their type 2 with keto. you will lose more than just fat on keto and a calorie deficit and it makes working out harder for some people since our muscles and brain get energy from glucose.
"good" carbs are your friend as insulin helps the body synthesize protein significantly and will lead to faster muscle growth and waste less protein.
if you have kidney problems avoid any protein supplements that contain creatine, but if you don't, it'll definitely help!
i started like you with only dumbbells about 5 years ago. i regret not getting a pullup bar early on and learning to eat the right foods and supplementation. i was on keto and a calorie deficit, it made progressing very hard and i became very skinny.
you will get a variety of answers on how to accomplish your goals depending on who you ask, so just do your research, find what works for you and stick to it. don't be afraid to change things up when things get boring. try to make friends with people who are really into weight lifting or fitness to get advice and motivation.
hopefully, this helps you as much as it helped me. i was 250lbs with no visible muscle at all, probably well over 40% body fat, man boobs and all. keto brought me to 142lbs and skinny as hell. i'm now around 190-195 with a chubby belly 4 pack and a physique that puts the old me to shame. also, get ready to receive much more attention from both men and women, lol.