Your screenshots won't show up until the forum moderator checks them.
However, all I see in the Dell downloads is the Realtek driver, no other sound enhancements.
For best audio operations the Dell driver should be used. We have seen audio problems on some with non-Dell provided sound drivers.
Finally, the OptiPlex line is sold as a business system, not a gaming or entertainment system so there is no need for audio enhancements by most users. An add on sound card with the capabilities you want is the best option.
Dell forum member since 2002
Dell Inspiron 15 - 5577 Laptop
Home Built Desktop PC with ASUS ROG Z170, i7 6700K CPU
Windows 10 64 bit Pro and Windows 10 Insider Program Beta Versions. SSD drives. Cakewalk by BandLab and Studio One 4.6 Pro Recordng Studio Software.
Dell S2719dgf Monitor
Member of Nashville based R.O.P.E.
DTS Studio Sound - This package contains the drivers and SoftPaq application with GUI for the HP DTS Sound Software.
I have not seen this on dell models.
Dolby®/DTS® Sound is not a standard feature for Dell.