If you’re already walking several miles a day, build on that. Challenge yourself to increase the pace of your walk - time it and see if you can knock some seconds off each day. Have you heard of rucking? Basically walking with a heavy weight in a backpack. It’s becoming more popular here, I think. Start adding weights to a rucksack and building them up.
consistency is key - of diet and exercise. You need to find a plan and stick to it like glue. No cheat days or ‘just a bit’ because you then spiral back to unhealthy habits.
if you can afford it, work with a personal trainer who can create a full plan for you. If not, look at apps and online programs. Take the work out of it so no thinking is required until it becomes routine. A friend used 6 pack revolution and managed to lose weight - she was told belly fat is 90% diet so you really need to address your eating.
No sweets / cakes in the house and every time you want to boredom eat, have a glass of water and make yourself wait 20 mins. You won’t want it after all.
Diet wise - cut out UPFs wherever you can. The more you have to do to prepare and digest food, the fewer calories are retained because you’ve burnt them off doing more work. And cut out rubbish carbs like white bread, white pasta, potatoes etc. which affect your blood sugar and can cause insulin spikes.
Are you in the age bracket for menopause? Hormones can have a massive affect on your energy levels.
Think about how to increase the calories burnt in every day life - called Non-Exercise Activity Thermogenesis (NEAT). Making small changes can build this calorie burn up so you’re working on your goal throughout your normal day - get off the bus 2 stops early, take the stairs (or get off the lift a floor below and build up). Stand to write emails / on the bus.
Take photos. You might not see much weight loss - and it may plateau after a few weeks, which will make you feel rubbish - but photos and measurements won’t lie. If you do the work, they will show you getting smaller.
Good luck!