Odata query where the property type of Date is in string?

I want to have below odata query.

$filter=(Program eq 'E6' or Program eq 'NON') 
and PricingCountry eq 'UK' 
and PricingCurrency eq 'GBP' 
and CustomerType eq 'USR' 
and LicenseAgreementType eq 'CRP' 
and StartDate le '2022-04-01T00:00:00.000Z' 
and (EndDate eq null or EndDate ge '2022-04-30T00:00:00.000Z') 
and (
    (PartNumber eq '9TX-00635' and ProgramOffering eq 'ACP' and OfferingLevel eq 'D' and PurchaseUnit eq '1Y' and PurchasePeriod eq 'AAS' and DealDuration eq 60)
    or 
    (PartNumber eq '9TX-00635' and ProgramOffering eq 'ACP' and OfferingLevel eq 'A' and PurchaseUnit eq '1Y' and PurchasePeriod eq 'AAS' and DealDuration eq 60)
)

I have written below code, everything is working except start date and end date as those are in String in Odata and i don't have control.

If i keep in string then >= and <= is not possible and language won't allow.
If i try to parse to DateTime or DateTimeOffset, package is giving error like its not able to parse.

           var start = DateTimeOffset.ParseExact("2022-04-01T00:00:00.000Z", "yyyy-MM-ddTHH:mm:ss.fffZ", CultureInfo.InvariantCulture);
            var end = DateTimeOffset.Parse("2022-04-30T00:00:00.000Z");

            uri = uri.Filter((x, f, o) =>
                    (x.Program == "E6" || x.Program == "NON")
                    && x.PricingCountry == "US"
                    && x.PricingCurrency == "USD"
                    && x.CustomerType == "USR"
                    && x.LicenseAgreementType == "CRP"
                    && x.CustomerType == "USR"
                    && x.LicenseAgreementType == "CRP"
                    && x.StartDate <= start
                    && (x.EndDate == null || x.EndDate >= end)
                    && (
                        (x.PartNumber == "021-05331" && (x.ProgramOffering == "CUS" || x.ProgramOffering == "NON") && (x.OfferingLevel == "A" || x.OfferingLevel == "NON") && x.PurchaseUnit == "1Y" && x.PurchasePeriod == "AAS" && x.DealDuration == 12)
                        || (x.PartNumber == "021-05331" && (x.ProgramOffering == "CUS" || x.ProgramOffering == "NON") && (x.OfferingLevel == "B" || x.OfferingLevel == "NON") && x.PurchaseUnit == "1Y" && x.PurchasePeriod == "AAS" && x.DealDuration == 12)
                    ), useParenthesis: true);

ZEXSM / OData.QueryBuilder

Odata query where the property type of Date is in string? #111