See here for alternative software:
https://www.toptenreviews.com/best-greeting-card-software
However I make my own greetings cards without using any dedicated software at all. I simply use a desktop publishing program instead. I make the outsides of the card (i.e. the fronts and backs) by starting with a blank A4 landscape page, dividing it down the middle and putting the back page on the left side and the front page on the right. (Obviously, it's also possible to produce top-folding cards instead, by starting from a blank A4 portrait page. I then put the front of the card on the bottom half of the page, with the back of the card upside down in the top half).
I simply get my graphics off the web. For example, here's the front of a Christmas card I knocked in just a few minutes from just two web images, with a bit of text added:
https://ibb.co/0t15MSP
I print the 'outers' of my cards (i.e. the fronts and backs together) onto A4 glossy photo paper. I then design and print the inner page(s) onto labels which are just a few millimetres smaller than A5 size:
https://www.a4labels.com/en-gb/white-address-labels-200-x-144mm
That gets around the problem of being unable to print on the reverse of photo papers.
Lastly, I put my cards into standard white C5 envelopes.
Any DTP software can do the job with ease, such as Microsoft Publisher or, for a freebie, the mighty Scribus:
https://www.scribus.net/