It sounds like your meetups are making you feel awkward and anxious and leading you to lose confidence and hyper self-aware of conversation skills.
Your friends seem like kind people but their lives are on a different path. This inevitably means you have less in common, so conversation and making a connection takes a little more effort and thought. If you're an introvert, you likely need a little more thinking time in the moment to process and formulate what you want to say, and that's difficult if you feel anxious about it.
If you find small talk tricky, there are few things that might help:
Firstly, it's important to recognise that small talk plays a crucial role in human interaction. Introverts are deep thinkers, and sometimes small talk can sound very trivial. Think of it as a chance to make a quick connection with someone, the opportunity to know something about them, a sort of verbal smile or handshake, which can develop into a deeper and more meaningful conversations over time. The actual words matters less than the intent, tone and effort. People like to feel heard, acknowledged and understood.
Secondly, understand that it's a skill that can be learned! It bears very little relation to whether there's any drama or action going on in your life. It seems counter-intuitive, but it is so.
Like any skill it needs a bit of research and practise, if it isn't something you're naturally good at. So practise - a lot. Practise small talk out and about where it doesn't really matter if it's a bit sketchy... at the supermarket checkout with the store assistant. Practise with the receptionist when you have an appointment somewhere, practise in your quiet neighbourhood when you're out on your walks.
Set yourself a target of trying out some small talk every day if you can - even if its just a 'Good morning' and a comment about the weather. It will reduce your self consciousness and anxiety around it over time, even it feels very unnatural and forced at first, and it will build up your confidence as well as your skills.
Thirdly, prepare a little. If phone conversations seem tricky, then keep a notepad handy and when you think of something interesting to talk about or that you've been doing, write it down. So, if you went to the forest, jot it down in the centre of a page and make a little mind map (I think they might be called spiderweb diagrams now) of how you might develop and extend the conversation. When someone phones you'll have a notebook of prompts to try out.
Fourthly, think of small talk as a fishing analogy. Someone starts a conversation with a question, and it's like they're throwing you a line with some tasty bait on it to hook you in. If you just give a one word reply, you've only just nibbled it and not let them to reel you in. Take their bait and swim towards them by giving a bit more of yourself in the conversation as far as you can. When you've done that, then it's your turn to throw a baited hook... what question, comment or compliment might entice them to swim/chat to you about themselves?
If you know you're going to meet up with someone specific, you can also make a few notes in the days/weeks beforehand to help with this - something about them you remember from your last conversation perhaps - about their family, their hobbies, job, home, holidays. After your meetups, write anything significant happening to your friends in your calendar so you can look back on ideas before the next time, Practise using these notes as a prompt to throw little conversation hooks to reel them in, and listen out for when they are doing the same thing to you.
Sorry, long post - hope it might be a little bit helpful!