I've never had a problem like you list, and I NEVER delete any restore points.
My Computer
At a glance
Windows 10 64 bitIntel i7 6700K16GB Corsair DominatorIntel CPU Graphics
Computer type
PC/Desktop
Computer Manufacturer/Model Number
My Own Build
OS
Windows 10 64 bit
CPU
Intel i7 6700K
Motherboard
ASUS ROG Maximus VIII Hero
Memory
16GB Corsair Dominator
Graphics Card(s)
Intel CPU Graphics
Sound Card
RealTek
Monitor(s) Displays
27" Dell S2719dgf
Screen Resolution
2560X1440
Hard Drives
1 TB Samsung 850 EVO SSD for Win 10 Pro
500GB Samsung 850 EVO SSD for Win 10 Insider
2 TB drive for backup
PSU
EVGA Supernova 750G2
Case
BeQuiet Silent Base 600
Cooling
Deepcool Captain 120EX
Keyboard
Microsoft Wireless 2000
Mouse
Microsoft wireless
Internet Speed
100 MB/sec (Cable)
Antivirus
Microsoft Defender and Malwarebytes
Browser
Edge/Firefox
Other Info
Cakewalk (Sonar) by BandLab and Studio One 4.1 Pro recording studio software. MOTU 896Mk3 Hybrid recording interface, Frontier Tranzport wireless control unit, Behringer X-Touch Control Surface.
Five USB connected optical drives for CD Audio production using Nero BurningROM
@chewtah. The reason for your slow starts might have been due to the amount of disc space that was allocated to System Restores. There is a slider you can use in System Protection in the Configure window that allows you to set the amount of disc space allocated to system restores.
You can adjust that to any setting, but you need to keep in mind that having a very small allocation will not keep many restore points.
My Computer
At a glance
Windows 7 Home Premium 64 bit sp1Intel i5 3570 3.4Ghz Ivy Bridge SKT 1155 quad...G-Skill Rip Jaws 16Gb (8x2) DDR3 -1600 PC3 12...Gigabyte NVIDIA GT610 1Gb DDR3 810/1200 PCI-E...