Here is my method from 85-99 that is profitable if you do it properly, I hope this helps some people who are looking for an afk'able way to 99.
Level Requrement: 85
Buy Around 1,000 Magic Logs from the GE if you do not have them already, as of right now they are running around 800gp each. If you chopped them from Woodcutting that's even better, use those to save some cash. You can also buy 1,000 Bow String while you're in the GE to save you some time. If they don't buy immediately just wait for it. By the time you're done with the next couple steps the order should fill.
Grab a knife, you can get one from Jackie located at home in the Northwestern most building to the left of the Achievement Hall or from the Wintertodt boss/minigame in one of the crates.
Change your bank withdrawal/deposit quantity to All and click on the stack of magic logs in your bank
Cut all 1k logs into Magic Longbows (u) and deposit them into your bank for safe keeping until you're done
Once you're done cutting all those logs into Magic Longbows (u), use the Bow String on the Magic Longbow (u) to make Magic Longbows (Magic Longbows at the time of writing this are selling on the GE for ~827gp each but they can be high alched for ~1,536gp each.
You can high alch all 1k if you'd like but for the sake of saving some time and if you don't have the required level to high alch you can just sell to the general store at home or at the general store in West Ardougne for close to alch price, this giving a decent profit as well as a boat load of experience.
Rinse and repeat this process to 99!