i'll probably end up echoing the same things mentioned in the other replies, but i hope i can be of help.
opioids are usually painless, but can very unreliable (unless you're using pure fent or h). prescriptions opioids are especially risky because they usually contain anti inflammatory meds that can damage your insides if you survive the od—which you likely will. tbh, just avoid attempting to ctb with any prescription drug.
if you think your train is too slow, i wouldn't even risk it. that's just me, though. plus, the si would be horrendous.
don't even attempt anything with the razorblades. it simply won't work.
pleaseee look through the sticky threads, the ctb resource compilation, and the pph. there is an abundance of information in these resources.
i would also suggest searching the forum, of course. for example, let's say you're looking into ctb with opioids. i would just look up 'opioid' in the search bar and go from there. many people share their experiences with failed attempts and nde's. there are also many people who have witnessed others die from specific methods and they make threads documenting what they saw and even how the other person felt throughout the process (this is most common with sn, but i'm sure there are similar threads pertaining to other methods). this can help you get a good idea of what different attempts could feel like.
still, i think you should use the sources provided in the sticky threads before anything else. at the end of the day, this is the internet and the users here can be unreliable.
also, the pph includes a comfort/lethality/accessibility scale for multiple methods. this site (which is featured in the ctb resource comp) also includes a similar graph:
For information on the most lethal methods of suicide, a good starting point is the statistics on the number of successful suicides by method (see Suicide statistics). There is also a much published study from 19951, where 291 lay persons and 10 forensic pathologists rated the lethality, time...
lostallhope.com
please stay safe, i hope you can find some peace.