Any way / tricks to get iPhoto to run on Ventura

There is no full, supported version of iPhoto compatible with macOS Ventura.

The last version to support iPhoto is macOS 10.14. There are some hacks around to be able to run iPhoto on macOS 10.14 Catalina or later, but it is not a full version of iPhoto, just an emergency solution to access your photos.

I recommend strongly to create a Photos Library from iPhoto Library, while you are still running macOS 10.14.

The new Photos Library will not need much extra storage, because it will store the photos with hard links to iPhoto. You can still work with iPhoto, but will be ready to switch to use Photos to access your photos, if you have to abandon iPhoto.

You are now running the last version of macOS, where you can easily convert the iPhoto library to a Photos Library and preserve the events as albums and can open iPhoto and Photos at the same time to compare the migrated library to your original iPhoto Library.

If you have to replace your Mac with a new Mac sooner or later, it will come with macOS 15 Sequoia, and you will no longer be able to migrate the iPhoto Libraries as completely as you can now. You will be limited to import the media from iPhoto and lose even the albums, folders, keywords. Now is your last chance to get the best migration, including events as albums, albums, keywords, titles.

The second reason to create yourself at least a Photos Library now are the radical changes in macOS 10.15 or later, when Apple removed the support for 32-bit frameworks. After upgrading to Catalina, some iLife frameworks will be missing, that are necessary for some older image and video formats. you should be prepared, that some older videos or image files in your iPhoto Library will no longer be supported on the more recent 64-bit only system versions. These have to be weeded out and converted while still running a system version that is able to open and convert these media. After upgrading to Catalina or later you will need third party apps to convert legacy media. There is no equivalent list for Photos, but this list for iMovie should give you an idea, which videos and photos need attention before upgrading beyond Mojave: About legacy media in iMovie for macOS - Apple Support

The Retroactive version is just a crippled version - all frameworks needing 32-bit code are missing, but better than nothing. Be careful, and use it only to browse your libraries to access the photos.

I am not sure, why you are not seeing the events, when you migrate an iPhoto Library to Photos.

You should be finding all events in a folder "iPhoto Events" as albums. But you have to do the migration before upgrading to Ventura, after that it will be too late.

There are quite a few apps, that are allowing you to keep the photos in folders in the Finder and are not enclosing them in a database. But I have not tested them thoroughly and cannot recommend any as a replacement. I prefer my photos to be protected from accidental deletion, by letting an app manage them.

Horning in on the conversation: I had this picture of continuing to use Betamax because it's better than VHS, when I'm the only one I know who even still has a VHS player-- most people I know don't even have a DVD player anymore. (I do, of course.) There are a number of things that I wish Photos did like iPhoto, but there are many, many things that Photos offers that iPhoto never thought of. It's tough to use Betamax in a Streaming world.

Most people who are making the transition use PowerPhotos ($30) to convert iPhoto Libraries to Photos. PowerPhotos evolved from their iPhoto Library Manager that most of us depended on, so these are people with plenty of iPhoto experience. Here is a discussion from their website:

Converting iPhoto and Aperture libraries

I bet that they would have suggestions for you, if you want to ask--they're pretty nice folks.

But léonie is really the iPhoto expert. Since you can boot into any OS of the past, she may suggest that you bring up macOS 12.0 Monterey (maybe) and do a direct migration there. Frankly, I barely remember iPhoto, and I'm just throwing in my un-inflated 2¢.