There are lots of e.d. drugs on the market apart from the well known ones. Before dropping a whole ton of cash on a hyped up expensive treatment, at least try a few more different drugs. There is probably something out there that suits you better.
A lot of men are using the new style of cock ring made of elastic rubber, such are made by Oxballs. The old school uncomfortable metal rings belong in the age of the plaid shirts and VHS tapes. Such cockwear will not create an erection alone but when you do get one they help you to stay hard for a long time.
So how about you try one of the shorter acting e.d. drugs, which are less likely to cause a headache, combined with an comfortable Oxballs type ring to extend the duration.
Shockwave is the nuclear option, try all other possibities first.