Kaphotics

Since you modified one of the immutable values, HOME will know and will reject it if you try to move it back in. PKHeX does not know the HOME upload data, it only has the data from the sav/PKM. You can try manually transferring it back to Gen7 and then retry transferring to HOME until you get a satisfactory value, but that's something that HOME can potentially detect in the future (importing same values).

string buffers are allocated and reused, meaning that the previous usage of that memory may have had data (not zeroes). renaming a pokemon does not clear the buffer, so longer nicknames will remain hidden underneath the new nickname & terminator. for generation 4+ encounters, you are fine grabbing from the database without modification; gens 1-3 do have trash bytes that are poorly understood, but don't matter when transferred to recent games (cleared/reset).

Latest development build of PKHeX has a setting that you can turn on to retain the met date for 4->5 transfers.

It means it failed to validate the encounter slot RNG correlation, which likely means it's not legal. The severity of the check is currently Fishy for Gen3 as vblanks may cause it to be disjointed, but in 99% of cases it's a correct assessment. How to remove it? Only assign PIDIV spreads that the encounter slot can have. Use a tool like Pokefinder to search.

Likely not; verify you installed the required runtime: https://learn.microsoft.com/en-us/dotnet/core/install/how-to-detect-installed-versions?pivots=os-windows

So, how to "fix" it? To start, I rearranged the 0x1000-sized blocks in sequential order (based on their offset 0x0FF4 value); since blocks 5+ are for box data storage, I can "copy" block 7 and re-label it as block 8; sure the data might be corrupt, but it's better than an entirely missing block. Probably wasn't anything lost, because now that the save file opens in PKHeX (and emulators/cart) it seems you didn't store anything besides boxes 1/2 and 14. POKEMON SAPP_AXPE-0.sav

Referencing the structure of Gen3 saves, your save file is missing necessary blocks and has duplicate blocks. Missing: Block 08 Normally, the save file is 14 blocks for a primary/backup, and another set for the other save. This one is a little all over the place, probably because blockwise writing failed once and it never saved the primary/backup sets completely (only one full set, kinda).

If it doesn't load in an emulator or on the bootleg, it's likely toast. Open the file in a hex editor and compare the contents to a valid save file to see if the contents are even sane

Hack your console by following guides online, and use homebrew to export your save file. Once you obtain your save data you can then load it with PKHeX; otherwise you won't be able to edit your Nintendo Switch save data. Stuff like this is unrelated to the operation of PKHeX, hence why it isn't explained in detail by the program. It's not going to know how to interpret any file you drop into it besides "not a supported file".

Because the mystery gift file does not contain any data on which games can receive it, and nobody has encoded a table for programs to use.

Added a flag in Settings you can toggle for the Entity Editor to show Gender in Gen1 contexts. https://github.com/kwsch/PKHeX/commit/b60648627a53c3dc12799f0d91d2cc7a0061aa02 Currently only in the development build, but will be available in future releases.

Export your save data correctly, that doesn't appear to be a save file that you've exported with homebrew.

Gender doesn't exist in Gen1, so it isn't shown. It was changed approximately 2 years ago. Sure the gender value would be the same as it is if it were transferred to Gen2, but again, it isn't shown because it could confuse users as it's not a feature in Gen1, and it doesn't seem like it would be much value added to show.

Do what the message box says. You need to install the runtime for the program to work.

Consider multiple languages. Gen3 does not store a flag in the pkm data; if the nickname bytes do not match the game (language specific) name, then it is nicknamed. Gen4 does store a flag; and changing the nickname to match the species name will un-nickname the pokemon. https://bulbapedia.bulbagarden.net/wiki/Nickname#Changing_nicknames