Looking for advice, switching from Ardiono IDE and MCUDUDE cores

Hello, First I want to say I’m sorry in advance if this post is a duplicate or if it is in the wrong section. Feel free to move if need be.

I am coming from using the Arduino IDE. It has been my go to development platform for 10 years due to the fact that I can find many many helpful libraries (now manged through the library manager) as well as 3rd-party cores for bare chips and non-arduino platforms. My current work flow makes use of the MCUDUDE cores including the mightycore, minicore, megacore, etc. I have used every single one of them. I also use a few other libraries to streamline development like fsm libraries and timers/task schedulers. I have been looking to move to a more mature code platform like atom and I noticed platform.io has a package for developing arduino code and uploading using Arduino as ICSP and USBtinyISP. I also see the it supports the mightcore from MCUdude, however I see a lack of the other cores he has as well as a lack of options for each core’s fuse bits like the clock frequency and BOD.

Specifically I need to develop a large firmware package for a Atmega 1284 with a 20mhz external crystal and Link time optimization support (is that even necessary outside of Arduino IDE?) I also want to import some 3rd party libraries I already use in the Arduino IDE.

Is this possible, or is support for bare chips limited at this time? I mostly design my own PCBs and use megas and 1284s, sometimes i also use the ATtinyCore for attiny85/84s when I can use them (this core has spi and I2c libraries built in for the attiny chips)

TL;DR: I want to start using PlatformIO and Atom for my 1284, ATtiny, and Mega2560 bare bones chips with options for frequency, internal or external oscillator, BOD, Bootloader or no bootloader. Basically the way MCUDUDE and ATtinyCore do it currently in the Arduino IDE. I also want to use Arduino libraries that I already use and know. Can I do that with PlatformIO and Atom?

PS. I noticed debugging tools as well. the 1284 has JTAG pins, is there a way to have hardware debugging?

Thanks for the help
Guess I’ll just stick to using the Arduino IDE since no other IDE offers support for installing MCUdude cores with selectable clock frequency and BOD fuses.