Weight loss should be a secondary goal. You need to focus on the end goal of re-calibrating your diet so that you can improve your life. The reason you can't exercise has much to do with what you are dealing with in the body.
An endocrine specialist might simply order a base thyroid test and say "everything looks normal keep losing weight."
What you need is also the stored Thyroid...Free TSH helps find things. Sadly most do a basic panel. It's not that the thyroid is the be all end all.
Another thing to consider is carbs, spiking triglycerides is more dangerous to cardiovascular health than fat.
Fat is your friend. High protein be it legumes or meats. Grass fed beef is better, it costs more, but it is 30 percent less of the bad stuff you don't need.
Blood sugar and heart medications are just temporary patches...If you are taking a statin drug...stop. I'm sick and tired of jerks telling me that I shouldn't tell people to stop taking drugs the doctor prescribed.
The overwhelming evidence suggests that cholesterol is good...bad cholesterol and "good" cholesterol are one in the same, just different make up chemically.
In fact there is a well cited study of thousands of heart related issues and those with higher cholesterol had a lower mortality rate.
It contradicts everything we are told about cholesterol.
I suggest you take a detailed food log of everything. Then break it it down into carb content, sugar content, and glucose content. Anything that can be seen as a spike in glucose should be monitored and adjusted. This kind of number crunching can be done without hiring a professional nutritionist or diet specialist.
They use buzz word "glycemic index" and that can often be a bunch of malarkey. America went on a low fat craze and it was fortified with sugar in place of fat.
Eat fat, get skinny.
Another thing that will cause adrenal blow out, is cosmetic products and house cleaning agents. They all disrupt the endocrine system.
Did you know the largest organ in the body is the dermis...the skin...So think about doing an inventory and looking up the chemicals.
Skin Deep web site is good, but don't take the ratings as gospel. They have an index score and generally I think i would avoid products that contain one or more ingredient that scores about 4-7...
Soaps, laundry dertegent, hand soap...anything you put on your body, that will also affect adrenals.
Look at the bigger picture. I can guarantee that you will lose more weight and feel better if you look at the entire picture.
Sadly the western medicine system offers little band aid repairs with drugs, that make numbers look good whatever that means.
My cholesterol was "high" the doc wanted to put me on a statin. My b12 levels were borderline low...and the doc wanted to put me on a proton pump inhibitor and one of the side effects is b12 absorption.
If you take an assortment of drugs, look at the clinical trial data, it's nice
The bottom is that you are working hard at weight loss, but you've got to work smarter. Compile the big picture, break it down. Adjustments in dietary behavior will net you more energy to exercise. Nobody is asking you to run a marathon, but you've got to exercise to lose weight.
Give yourself some credit, if you got from 335 to 271, you took control and did something right.