Component Level Repair
BOARD LEVEL REPAIR
Most logic-boards can be repaired without having them entirely replaced as long as the damage is not too much. Clients often don't know that individual chipsets can be replaced by professionals outside of apple, so there are better solutions rather than entire logic-board replacement which is the only solution the seller provides to clients usually. I do board level repair anywhere from micro soldering, BGA work to programming chipsets. As long as the inner layers of the board are not terribly damaged, they can usually be repaired. There is usually no cost other than the diagnostic fees, If the board repair is not successful at the end. (tips/your support are always super welcomed)
Liquid Damage Repair
Liquid damage or corrosion damage can often be fixed. It just depends on how bad the damage is and how long ago the incident was and if proper actions have been taken after the incident. Remember that liquid does not disappear. It dries out and turns in to corrosion and becomes far more conductive as you wait. If you had a spill, its important to have it repaired/diagnosed as soon as possible. Do not tilt the MacBook in any position as liquid can travel and get in to the screen or other parts. Best action is to have it checked out as soon as possible.
NAND upgrade
M1, M2, M3 can enjoy an SSD upgrade. Please note that device may become slightly slower after the upgrade depending on the amount of upgrade. This is something often not noticed or told online on Youtube videos you have seen. For example 1TB storage with 4 x 256GB chips is faster than 1 x 1TB NAND chip. Some models are limited to how many NAND chips can get on them.
Data Recovery