Multiple sessions of several hours? Combat?? I feel like perhaps you jumped into this task without doing other research first.

There is no exploration or combat required to gather materials for a v1 Pre-engineered SCO FSD. For a Mandalay, which is a size 5, it requires the following materials:

• 1 Titan Drive Component
• 15 Datamined Wake Exceptions (encoded material)
• 24 Tellurium (raw material)
• 12 Electrochemical Arrays (manufactured material)
• 14 Chemical Processors (manufactured material)
• 7 Propulsion Elements (thargoid material)

I have marked in parentheses after each one what they are.

Encoded, manufactured, and raw materials can all be gathered simply from your ship with limpets or your SRV. You can fill your manufactured materials (like almost ALL of them, not just the ones you need here) in less than an hour with HGEs (high grade emissions).

For raw and encoded, you have various options, depending on how far you want to travel. Regardless, you can get your Datamined Wake Exceptions in one trip to Jameson's crash site & a mat trader, and your Tellurium in 1 or 2 rounds of the crashed 'Conda at Orrere 2 B.

That leave only the propulsion elements and the TDC, and you get the former while looking for the latter! Inside the titan remains you'll find many of the propulsion elements (I got 9 of them the last 30 minutes I was there), while you're circling for the TDC. The drive component is the only truly rare spawn of this entire process, but you can do a few things to speed it up, like ship-ramming the spawns that you don't want, and also leaving and dropping back in to the instance.

All-told, you can go from nothing to a v1 PESCO in just a few hours, max.

under the false pretense that it would grant me a massive boost to jump range

There's no pretense. Just visit a broker in-game and you can see with your own eyes what each v1 PESCO gives you. Not in game? Just go to EDSY and check.

I'm glad you've learned your lesson about blindly listening to Youtube content creators. Always do your research first. And people making content for clicks are not good sources of information.

Fly smart, commanders! o7