Welcome! I had also a lot of trouble visualizing. If you know you have trouble visualizing then I would suggest you don’t worry about having a aphantasia and just have Faith that you can develop it.
What helped me tremendously was getting The habit to draw simple things like a child . It might not seem helpful but it really did help me develop my visualization. I think that, as I created these characters and animals and simple things with the pencil, my mind needed to visualize somewhat to finally manage to create my own version of it. It was never a hundred percent logical is what I am saying.
Also, visualization exercises to get out of stressful times, like trying to imagine a loved one, perhaps a souvenir, a friend’s home or birthday party, the time I bungeejumped or last saw my best friend… I like to close my eyes and relive the moment I helped my nephew ride his bike, his smile, him jumping in my arms. Sometimes try to see how was my childhood home, my first girfriend doing something she loves… very personal things at first just letting myself go…
Through these I learned of myself that I did not have the best observation skills, which I learned goes hand-in-hand with visualization.
Googling develop observation skills brings up a lot of exercises for that.
I think what was really necessary was find a way to get away from are the pressure and stress when not succeeding. Then little by little, even if faded, images and places can be successfully used for memorizing in a Memory Palace, but that also takes a lot of different skills to be developed, a lot of time and practice.
The free website readspeeder, where you are taught to read in images helped me tremendously also and I strongly recommended with as many 5-15 minutes sessions possible per day. This actually improved my reading tremendously, as well as significantly developed my visualization. Woooo too much adjectives ! but the truth…
To a lesser degree, but definitely without which I wouldn’t not I’ve made it, other people’s examples helped me a lot. Like the ones of Dominic O’Brien, his audiobook ( sorry I don’t remember the name) being the one that created a Eureka moment for me and managed to get me to believe in the memory palace, with a simple guided memory Journey. Alex Mullen or Nelson dellis YouTube videos also.
I had to give up countless times and during just as many months before I finally managed to break through to using palaces successfully and satisfactorily.
Starting with just about the simplest and least amount of images that you can think of. For example, let’s say place in huge smashed up apple on your bed, a jumping banana shaped fridge instead of your fridge, have a hippopotamus take a bite out of it and an elephant acting as a stove putting out your burning turkey with its trump…
Play around, have fun, and you’ll be starting to make images out of more and more complex things. You can find amazing and countless examples on this forum.
Today I use them daily.
Perhaps if you would share with us your process with more detail.
Cheers! And welcome again to the forum!