This thread is quite an education in how nasty some modern amplifier designs can be !
Thinking about the potential for repair and what the OP is trying to achieve..... I would say “go for it” and try to repair the amplifier if it is not too expensive for the components. It is a learning exercise after all and, thanks to the comments in this thread, the OP now knows a lot more about why the unit failed.
Just for the experience and fun of the challenge I would repair this board
First the PCB damage....... I would cut out a rectangle of PCB that encompassed the badly damaged area. I would then either insert an etched replacement PCB section or a piece of prototyping FR4 board that has the through plated holes in it. The replacement section needs to be securely mounted to the original PCB. I would use a combination of epoxy resin adhesive and brass strips soldered to 0V copper plain. The exact details depend upon the PCB topology. Once the OCB hole is filled the replacement components can be refitted.
Regarding the replacement components and considering that this is a bit of a learning experiment..... I would reuse the inductors and Common Mode Choke. I would rest the discrete components like transistors, diodes etc. If they test OK, you have the choice to reuse or replace as desired. Replacement is advisable if the components are suspected of having been stressed in the failure event. Now the controversial comment..... for the sake of this experiment and to discover whether this amplifier has any life left in it, I would purchase high quality very low ESR electrolytic capacitors, such a some nice Panasonic types and fit these into this amplifier. I know that this just repeats the OEM error but it will work to test the amplifier and is affordable. If the amplifier works then the OP can discuss potential capacitor upgrade paths and costs. There is no point in buying high quality expensive capacitors only to find the amp has issues that are not worth repairing.
Now if a prototyping PCB has been used in the repair, new PCB tracks will need to be created using suitably dimensioned copper wire. I would strip such copper wire from common 2 core and earth mains cable that is available in various sizes. It solders well and is more than suitable for the task at hand. The new copper tracks are soldered to the component leads on the underside of the PCB to recreate the required layout. As with a proper etched PCB installation (if used) there will be a need to connect the new PCB to the surrounding original with with copper wire. What you will end up with is a replication if any missing or damaged PCB traced using round cross section copper wire. It may not look pretty but consider it ‘artistic’ !
I have had to repair irreplaceable PCB’s in this manner to maintain mission critical systems or to maintain operation until a new PCB can be made/procured. It works well if done properly and with some thought. An example is high value spectrum analyzer that was dropped. The CRT PCB flexed so much due to the weight of the LOPT that the PCB broke in half ! I field repaired that CRT board after a visit to the local model and DIY shops. I repaired that PCB using brass strip, brass box section and copper wire from 2 core and earth cable. It actually looked quite pretty when finished and is still working to this day, 10 years later ! I shall have to see if I still have a picture of it.
So let us get back to the OP’s PCB. I see it as eminently repairable and a very useful PCB repair exercise. Provided the OP and owner of the amplifier understand why it failed, that it will likely fail again if electrolytic capacitors remain in the failed section, I see no harm in proceeding. It will be relatively cheap to repair in terms of getting it running anyway. PCB repair is a skill worth learning and this is a perfect opportunity for the OP as it is a simple PCB design. I was trained to be a component level repair tech but that also included repairing the actual PCB material in cases such as this. There are many techniques available for such work including careful layer reveals in conical PCB ‘excavations’ and epoxy filler repairs with new PCB traces adhered to the repaired sections..... it is an art and patience is essential. Well worth playing with a simple PCB to learn the basics though. Knowledge and experience can be of far greater value than the item being worked on
At the end of the day, if the amp is still dead after a repair attempt, the OP has learnt how to repair a holed PCB and so there is value in that.
There is quite a lot of information on holed PCB repair on the Internet and those considering undertaking such a task may benefit from some reading first as there are some great techniques worth learning.
Fraser