Good for you on wanting to take this step. Biking can be very addictive. Honestly, the first few rides won't be that much fun. Your whole body will hurt, especially your sit bones. As you go more, you'll get faster, your body will get used to it, and you'll start to enjoy each ride more than the previous ride. So don't get discouraged if your first few outings aren't what you thought they would be. Keep a realistic outlook on your biking progression.
A good bike recommendation will depend on your wallet. I would plan to stick in the $1,000 to $1,500 range and get a good quality hardtail. Rear suspension will just add unnecessary weight and you'll have to drop down in quality to stay in the same price point. At your size, a $250 Wal-Mart bike will not last long at all and it will suck to ride. Most of the name brand bikes in the $1,200 range will be durable enough to get you out and pedaling for a good number of years. One thing to remember is that you'll will wear out components quicker than a 150 pounder as there is greater load on everything. Contact your local shops and see what they have in stock. Covid has really chocked up the supply line so you may have to buy what's available rather than what you really want. Definitely take a test ride around the parking lot and see what fits you right. I'd say an extra large would suit you well but some larges may fit too.
I'm in and out of my local bike shop on a regular basis and they sell Trek, Otso, and Transition so I'll stick with those. Well, really just Trek as they have the bikes in the price range. Either the Trek Roscoe 6 or the X-Caliber 7 would suffice and both retail for around $1,100. The shop can help you set up air pressures in the tires and in the fork so it rides right and you'll want the pumps to keep them topped off. Another recommendation is to find local group rides and don't feel intimidated as a beginner. Before Covid, our local shop did Monday night rides at 6pm for all abilities. It would generally be between 5 and 18 people of all different abilities who just wanted to ride bikes. Those are the groups you want to gravitate towards, the ones that do not care what speed they are going or what terrain they are on, as long as they are riding bikes, they are happy.
Good luck and keep us posted on your progress.