OP, you have zero issues.
Since you ask about repercussions of overstays. Overstays such as a few days to a week also are not a problem regarding obtaining visas.
Be aware that for obtaining a PE (elite visa) it can be an issue with multiple overstays.
OP, this topic comes up but most threads are in "general topics" forum.
Here is one for example with lot of helpful threads.
Apart from that....imo leave it all.
Chuck it apart from the music gear.
OP, exit Thailand as planned without reentry permit and write off you ED visa.
Return when appropriate with tourist visa and access your options.
Land borders open now for border bounces to extend your stay.
I'm only quoting as it's a very naive post and could mislead folk.
You are not applying for an annual extension.
It's a basic reentry permit.
At BKK they even do the paperwork for you for 200 baht if it's too much of a challenge.
It is valid till your permission of stay date in your pp.
The expiry date of your extension matches your reentry permit.
A multiple reentry is 3800baht.
Single reentry 1000baht.
As mentioned by @ThailandRyan a tourist visa is best option.
That give 60 day stamp and can be extended by 30 days for a fee of 1900baht.
If you require longer you can add a border bounce with a visa exempt entry.
Does not need to be "just before" exit from Thailand.
When you do your first extension that sets the date for future extensions.
Obviously you will choose a date that fits in with your travel pattern.
When that date is established then future applications for extensions can be made up to 30 days prior to that date and 45 at some offices
Some time back I needed to have my stamps and visa info transfered to new passport at CW.
No problem however when I went to reentry permit desk they would not transfer reentry permit stamp as it had been issued at DMK and not at CW.
Just traveled internationally with both passports until next extension.
Geez.
There will always be potential for "personal treatment" from an io at office here and there.
In the main the extension stamps are obtained in places such as KK.
The passports are sent up country.
In turn this can present issue for 90 day reports.
Most agents offer that service also.
Regarding your "friend" ..he ended up with agent obtaining a non O retirement and 12 month extension for 20k.
This reminds me of Dreamworld.
Which agent and where were stamps obtained.
Agents offer various services.
What I am referring to is extension to non O retirement where no funds are provided by client.
As this fragmented from the OP.
Post a first hand experience of this type of extension obtained at Jomtien (without correct financials) along with agent name.
My last post on this as it's off topic.
I took friend who lives in Bangkok to Pattaya as being 48 did not qualify for non O retirement.
We went to Key Visa and the non O volunteering was obtained in KK.
Extension retirement would be same.
The thread is about report back 3 month post application requirement.
I have assisted (advice) many folk re extensions retirement and other such as non O volunteering.
If you have personal experience of using Pattaya agent and them obtaining extension at Jomtien immigration then by all means post details as I'm sure many would be interested.
Saigon is great place.
You could obtain tourist visa there and also make holiday out of it.
Thai do not require visa and also German national same.
Just check visa exempt for Vietnam back in place .
You are permitted 2 visa exempt entries via land borders per calendar year.
Each visa exempt entry can be extended by 30 days.
Referred to as border bounce.