Your e906 is designed primarily to be stuck in front of guitar amps, I'm not surprised that a Rode LDC would beat it. That does not mean that everyone recording in their bedroom will do better with a condenser microphone vs a good dynamic.
I think you'd be best seeing how far you can get with your current laptops before upgrading. On the software front Reaper would be an excellent choice on Windows, very cheap and CPU efficient.
Cheap audio interfaces have come a very long way, I'd look at what's being sold second hand in your area. Something with a Hi-Z input if you're wanting to record your guitars directly though the interface.
The Strymon Iridium is fantastic, if you have more to spend and want more flexibility Kemper profilers are hard to beat. AxeFX also gets a lot of love.
On the more budget end most audio interfaces these days will have a Hi-Z input for guitar, there are many great amp/stompbox emulation plugins these days.
I adorrrrre my Iridium. I have Guitar Rig & Bias FX and a bunch of other sims, but the Iridium is really special. The sound is _inspiring_ - in that it makes me want to just sit and play guitar for hours on end because it sounds so damn good. It's expensive and I try to not be a gear addict, but imo investing that much in my joy was money well spent.
I don't think you'll see any appreciable difference in conversion quality by switching audio interfaces at this level, particularly with the style of music you are making (which is great by the way, well done!). It all comes down to workflow, and it seems you're getting it done just fine with the Yamaha. I'd look to upgrade if you find yourself needing more inputs.
The more obvious upgrade would be a new microphone to replace the Kenwood you are currently using. An SM-58 will last you a lifetime or if you have a bit more to spend something like an SM7b will be a great investment particularly recording in untreated spaces.
Also, you could try recording the midi information of your electric drum kit and then loosely quantising/editing the takes to retain the feel. You can map these to Logics in-built drums which are pretty great.
Congrats on finishing a body of work, most don't get that far!
Thank you for your suggestions, and specifically on the microphone one. I wanted to get a new one but I was having some difficulty choosing a good one for me. I will look into this. And thank you for your nice words!
Yeah going down the microphone rabbit hole can be confronting. It's always best if you can try a particular model before purchasing it (particularly for your own vocals), as microphones are very source specific.
Not always an option depending on where you are, but often you can find an audio-rental company nearby. It's hard to go wrong with the mics I mentioned above though. Keep it up!
