I can't see older version even after hitting the dhow older apps button on preferences

Make sure your computer meets the minimum CPU & GPU requirements. Most Creative Cloud apps work on:
Windows 10 versions 21H1, 20H2, 2004, and 1909 (LTSB branches are not supported);
macOS 12 (Monterey), macOS 11 (Big Sur), macOS 10.16 or 10.15 (Catalina)
- https://helpx.adobe.com/creative-cloud/system-requirements.html
- https://helpx.adobe.com/photoshop/system-requirements.html
- https://helpx.adobe.com/photoshop/kb/photoshop-cc-gpu-card-faq.html

Old versions are NOT available to trial members.  Regardless, your OS is not supported anymore. 

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Adobe only offers the current and ONE older version... and I don't think your old operating system is supported for what Adobe offers

I do not know how far back this process will go, but try...
Direct Download Links https://prodesigntools.com/tag/ddl MAY help
-you MUST do what it says in Note: Very Important Instructions
-https://prodesigntools.com/adobe-cc-2015-direct-download-links.html#download-instructions
-the prodesign links go directly to Adobe's file server, so this process will
--only work until Adobe completely removes the old version(s) from the server
.
IF/When you do have a download, be sure to copy it to AT LEAST one external device
-since Adobe does sometimes remove old versions from the server
-a usb flash drive or external hard drive, or write to a DVD