Using something like Graphene OS or Lineage will result in less ad tech monitoring you, which may be useful in the event of sudden increased persecution (worse than what exists).
Keep your phone in airplane mode unless absolutely needed to avoid providing information about your routines that can be used maliciously by corrupt government forces. The government doesn't need to know your route home, so go into airplane mode!
KryptKey is an excellent FOSS App and that allows cryptography in regular text messages. If a conservative coalition blocked VPNs, KryptKey provides ways to communicate using traditional methods if certain servers for encryption Apps are blocked.
A low tech way of letting people know you aren't being held or killed is to update your voicemail with the date. For example. "Hi, it's me SATL. Today is April 2nd as of this recording and all is well. I'm still a Windows user not spending all my time on a Linux addictuon! Leave a message after the beep." A failure to update the message for an extended periods could indicate a problem. Because people can sometimes get arbitrarily banned on Facebook for no reason, relying on Facebook for this function is a bad idea.
Community Assistance Groups using SimpleXChat: create a group using SimpleXChat of other marginalized people and make certain agreements. In the event anyone is missing, the remaining group members will place at least 10 calls per day trying to find them, and if they know where they are they will continue to each spend at least 10 minutes per day trying to make contact. The reason for this is if you are locked up, you can only hope people are trying to find you, but a contract like this let's you know in advance people will be looking for you, providing comfort. The rules of the groups could be modified as needed.
Go Bag: everyone needs a good go bag. When you really need to flee, your ability to this plan is going to be diminished because of stress. Stress result in flight or fight: logic skills go down and running speed goes up. That's why you want your go to bag packed beforehand. You should know that when the emergency happens, you will always accidentally leave somethings behind. So a go to bag, in any easy to grab spot, helps and if it's economically possible don't take stuff in and out of the bag. It is very important to already have a different burner phone ready to go with a different IMEI, preferably with Graphene OS installed or Lineage. You must not connect to any accounts like Facebook with this phone. Instead, use SXC and invite your contacts to the burner phone before you leave or reach contacts using Signal, storing numbers in the Graphene phone using a notepad App. It maybe beneficial to get a non-Graphene phone with a removable battery so you can keep the battery out of your phone unless needed if you wish to be especially careful.
Plan to flee: if you plan to flee, having a go to bag isn't that helpful without a way to eat and sleep. Consider a sleeping bag or tent, car, and cash. Consider bags of rice, noodles, and oatmeal to keep locked in a car as well as plastic bowls. These items can be edible with gas station water given a long enough wait for them to become less hard and dry
Know the route to take: if you notice someone following you and expect you are being sent to an oppressive prison, you may wish to flee to Mexico or Canada and then depart from there to another country to avoid inhumane treatment. Have an exit plan in advance and know which way you intend to go.
The biggest threat marginalized people may face is if VPNs and other remote encryption technology are banned. A result of this could mean Signal Servers are banned, SimpleXChat servers are unreachable, and there is no way to send secret messages. This is why it's so important to download KryptKey now, not later.
Briar can work via Bluetooth even if cellular technology is down. It should be in every emergency phone.
Financial prudence: with prices going up and the economy being difficult, sometimes just surviving is a victory. But if you can, be careful to save, lower expenses, and be strategic with money so that you can be more ready for emergencies.
What can less marginalized folks do to help? Offering an coffee/sleepover area for any of your friends to stop by is a wonderful way to connect with your neighbor, like a modern day salon! You can get the games and crackers and snacks in advance and have pillows waiting for anyone who needs to stay the night, as well as some pre-selexted philosophical topics. "Do parallel universes exist? What is the best food and why? Do NPCs really exist? Why or why not?"
Please add suggests or criticisms.