Bupe withdrawals are definitely painful and prolonged. Not quite as bad as methadone but up there. 1.5mg is not a lot but enough to still have unpleasant withdrawals. I suggest you continue to taper to 0.25-0;5mg or so. Getting off that actually isn't that bad. It's tolerable. Gabapentin could help. You can even go lower on the bupe than that. To get tiny doses of bupe you can dissolve the pills/strips in alcohol, measure an appropriate dose, and hold the alcohol/bupe solution under your tongue instead of the pill/strip. It's a bit tricky but it works.
Switching to oxycodone when you have the option of a full bupe taper is questionable. Yes, withdrawals would be not as prolonged but you would probably wind up on more morphine equivalents than you were on the bupe which is it's own issue. If you switch to oxy the best advice would be to taper to a lower dose of bupe anyway and then way 36 or so hours so the oxy is not wasted when you switch over. But then, why not sweat it out and get off bupe entirely?
What's the endgame? Going back to recreational opiate use (as is suggested by having a bunch of oxy's on hand) or getting off opiates? Advice would be different depending on which.