I agree with your points, I know the pain as I was there not long ago, about 3-4 weeks ago, if I can do it you can do it as well.
Make sure you use a live oak/white oak or wo/wo ship for missions. Also try to get elephant bow figure or planking book for 6-7 rates, basically it's recommended to have the armor hp/thickness and reload maxed out (+25%). Use carronades and get the carronade master, emergency repair perks. Also, get the fleet ship perk and learn how to use it, I would mostly just use it to demast and slow down the other ships while not impacting too much your exp gain. Please let me know if you have any questions!