Trying to jump from 25% - 10% can be extreme, especially if done to quick. Imo, just start w the basics of cal deficit and fine tune from there. If ur working out 5xs a wk then ur cal deficiency is more than 500. Closer to 800/900cals depending on type and intensity of ur workouts. Being aware of cal surplus/deficit and macros are the first step to achieving ur goal. Next is figuring out where those macros need to be? Our goals and bodies are all different so living in this part of dieting can take longer than others w more experience. But through dedication and consistency ull still get results. The app myfitnesspal really helped me learn my personal proportions and fine tune my macros. Dont rush this, enjoy it, live it. 25%-14% for first stage. Then readjust to more advanced dieting after.. Just my opinion, but glad to see u working towards a goal brother.

How long? Don't you think that depends on what you do? If you do it wrong and are lazy it could bear little results. however, if you do everything right and go at it full effort the results will be a lot faster. 25 to 10% is a BIG drop so bear that in mind.

I’d say 6 months if you lock it in and really follow a plan.
Could be closer to 12 if you half ass/don’t know what you’re doing. It’s all variable. These figures are based on the fact that you’re asking the question in the first place which leads me to believe this is not something that comes easy for you.

John meadows has some good diet videos on how to structure your plan. For long term progress, (the kind you need) the key is slow and steady. You change one component of your daily routine and let that run it’s course. Then change another until the loss stops. Then another. Then another. Slow and steady.

Figure your TDEE, get a food scale, meal prep your food so you hit all your macro goals. I don’t believe in fad diets, carb cycling can help but be prepared to feel like death on 50g carb days. Add a good 30-45 minutes of cardio 4-5 days a week, yeah it sucks but think of it as keeping a healthy heart as well as helping along the fat loss. Without AAS you can make that cut in about 90 days give or take.

If your diet is on point and perfect you can drop 1% per week. But it doesn’t would like your counting your calories, carbs, protein or fats. So get help with that first. It’s 90% diet and more complicated than just “eating meat and veggies”.

Not an expert on dieting but Ketogenic diet will help drop fat fast of course you will loose some strength and possibly size in the process
You’d have to adjust your training method also